Discover Your World with NOAA

National Oceanic and Atmospheric Administration

U.S. DEPARTMENT OF COMMERCE

NAT OI NAL OCEANIC AND ATMOSPHERIC ADMINISTRAT OI N

From the edge of space to the bottom of the ocean...

Tate Nation

An Activity Book
The Discover Your World with NOAA Activity Book was compiled and developed 

for NOAA’s Celebration of 200 years of Science, Service, and Stewardship 

under the direction of the

NOAA Celebration Education Working Group

Nadia Sbeih – NOAA Ocean Service (Co-chair)

Molly Harrison – NOAA Fisheries (Co-chair)

Karrie Carnes – NOAA Ocean Service

Kim Cohen - NOAA Ocean Service

Margaret Fowke – NOAA Weather

Ron Gird – NOAA Weather

Sami Grimes – NOAA Research

Jennifer Hammond – NOAA Marine and Aviation Operations

Jorgeann Hiebert – NOAA Research

Nina Jackson – NOAA Satellites

Jamie Krauk – NOAA Research

Elizabeth McMahon - NOAA Marine and Aviation Operations

Amy Painter – NOAA Research

Krista Trono – NOAA Ocean Service

Written and Edited by Mel Goodwin, PhD and science writer, Charleston, SC

Design and Layout by Sandy Goodwin, Coastal Images Graphic Design, Mount Pleasant, SC

Cover Painting by Tate Nation, Mount Pleasant, SC, ©2007 

Illustrations by Paul Rossmann, Charleston, SC

The assistance and expertise of the following reviewers for the revised version is acknowledged with thanks:

Ron Gird, Susan Haynes, Molly Harrison, Tracy Hajduk, Nina Jackson, Deborah Jones, Bruce Moravchik, Peg Steffen, Krista Stegemann, Marlies Tumolo

Revised and updated August 2017

For more information on NOAA’s history and time line, check out the celebration Web site, 

celebrating200years.noaa.gov/

For more information on NOAA’s educational offerings, please visit our Web site, 

www.noaa.gov/education 
Discover Your World with NOAA

National Oceanic and Atmospheric Administration

U.S. DEPARTMENT OF COMMERCE

NAT OI NAL OCEANIC AND ATMOSPHERIC ADMINISTRAT OI N

An Activity Book

National Oceanic and Atmospheric Administration (NOAA)

Science | Service | Stewardship INTRODUCTION

iii

Table of Contents

INTRODUCTION

Discover Your World with NOAA ................... 1

NOAA’s Building Blocks ..................................... 2

EXPLORE THE EARTH

Introduction ....................................................... 8

Boat Building Challenge .................................. 9

Make Your Own Astrolabe ...........................12

Make Your Own Compass ............................16

Tied Up in Knots ............................................18

Who’s Blue Peter? ..........................................22

The Water Writers ........................................25

Nautical Chart Challenge .............................28

Build an Underwater Robot ........................34

Earth Origami ..................................................37

Make Your Own Volcano! ..............................40

Do You Have Twisted Vision? ........................43

Be A Shipwreck Detective ............................47

Weird, Red and Slightly Gross! ....................51

UNDERSTAND THE EARTH

Introduction ....................................................... 55

Follow That Hurricane! ...................................56

Build Your Own Weather Station ..................61

Build an Anemometer ..................................62

Build a Weather Vane ...................................64

Build a Barometer ........................................66

Build a Screened Thermometer ................67

Build a Hygrometer ......................................67

Build a Rain Gauge .......................................69

Be a Citizen Weather Reporter ....................70

Tornado in a Bottle ..........................................73

Rip Currents ...................................................... 76

Be a Tree Ring Detective ................................78

Your Own El Niño ...........................................81

Please Pass the Salt ..........................................83

Satellite Communications ...............................86

Wooly Magma ................................................... 89

Survey Mark Hunting .......................................93

PROTECT THE EARTH

Introduction ....................................................... 97

Fish Fetch ........................................................... 98

The Ocean Drugstore ...................................100

Who Trashed the Ocean? .............................103

It All Runs Downhill .......................................106

Toxic! Or Is It? ................................................108

Invasive Species Super Sleuth ......................110

Your Alien Dodecahedron ............................111

Endangered Species Origami .......................118

What Are the Impacts of Shrinking 

Polar Ice Caps? ................................................123

Following the Ocean Unicorn .....................128

Make an Edible Coral Reef ...........................133

Now THAT’s Complex! ................................139

Fixing Our Earth .............................................142

SCIENCE Service STEWARDSHIP

National Oceanic and Atmospheric Administration (NOAA)

Science | Service | Stewardship INTRODUCTION

1

All in a day’s work for the people 

of NOAA as they put science, 

technology, and engineering to work 

for you. Every day, NOAA helps people 

with local weather forecasts, tornado 

warnings, oil spill cleanup, high quality 

seafood, navigation tools, and many 

other services. NOAA is also a leader in 

ocean exploration and environmental 

sciences, fi nding out more about the 

Earth and how to use and protect our 

planet’s resources.

NOAA’s motto is “Science, Service, 

Stewardship.” Putting that motto into 

action leads the people of NOAA from 

the edge of space to the bottom of the 

ocean. These activities are designed to 

help you learn more about our world, 

and how NOAA helps you to explore, 

understand, and protect our Earth. 

HAVE FUN!

Courtesy NESDIS

Discover Your World with NOAA

National Oceanic and Atmospheric Administration

1

Flying into the eye of a hurricane

Protecting whales, sea turtles, and sea lions 

Watching the Earth from 22,000 miles above the ground 

Diving into submarine canyons that could swallow Mt. Everest

Restoring marshes, wetlands, reefs, and other marine habitats

Saving lives threatened by tsunamis, tornadoes, and killer storms

Managing ocean resources and their habitat

Courtesy NWS

Courtesy OMAO

Courtesy NOS Courtesy OAR

From the edge of space to the bottom of the ocean...

From the edge of space to the bottom of the ocean...

U.S. DEPARTMENT OF COMMERCE

NAT OI NAL OCEANIC AND ATMOSPHERIC ADMINISTRAT OI N

Courtesy Todd Marsee, Michigan Sea Grant

Courtesy Robert Schwemmer, Channel Is. National Marine Sanctuary
noaa.gov

Discover Your World With NOAA

2

New Hurricane Hunter Aircraft

El Nino Makes a Comeback...

Entangled Whale Rescued

Lionfi sh Invade U.S. Waters

Satellites Relay Distress Calls

Astronauts Test Moon Exploration 

Concepts on Seafloor

Expedition Explores Underwater Wreck 

of Historic Naval Airship

NOAA’s

Building Blocks

Do you know what NOAA does? 

Play this game and fi nd out!

Deadly Heat Wave 

Reaches East Coast Courtesy NWS

Courtesy NOAA

Courtesy Paula Whitfi eld, NOAA

Courtesy NESDIS

Courtesy NWS

Courtesy NMFS

Courtesy NWS

Courtesy NOAA
National Oceanic and Atmospheric Administration (NOAA)

Science | Service | Stewardship INTRODUCTION

3

What You Will Need

❒ Jenga® or Uno Stacko® game

❒ Two sets of “NOAA’s Building Blocks Game 

Cards” – Make two copies of the “NOAA’s 

Building Blocks Game Cards” page and cut 

the cards out. The cards will last longer if 

you photocopy them onto heavy paper called 

“card stock” or “cover stock.” It will be easier 

to tell the di erence between “Problems” 

and “Solutions” if you use one color of paper 

for “Problems” and another color for “Solutions.”

How to Play the Game

1. Follow the instructions that come with the 

game. If you are playing with one or more 

other people, divide into two teams. Each 

team gets 24 blocks, and stacks these into 

eight layers of three blocks per layer. Each 

layer should be at right angles to the layer 

below. Shu e the Game Cards, and place a 

set of the Cards in front of each team.

2. One team at a time draws a card from the top 

of the Game Card pile. There are “Problem” 

cards and “Solution” cards. For every 

“Problem” there is a “Solution” somewhere in 

the pile of Game Cards. 

 If you draw a “Solution” card, read the card 

aloud and then:

(a) Keep the card until you need it to solve a 

“Problem;” OR

(b) Remove one block from the top of your 

team’s stack, and place the card in a 

discard pile separate from the Game 

Card pile.

 If you draw a “Problem” card, read the card 

aloud and then:

(a) Remove one block from any layer of the 

stack except the top layer, and stack it 

on top of the stack; OR

(b) Solve the Problem by reading a 

“Solution” card that your team has 

drawn and saved previously.

 When you have fi nished (a) or (b), place the 

card in a discard pile separate from the Game 

Card pile.

 Players may use only ONE hand when removing 

and stacking blocks! Blocks that are stacked on 

top of the pile should be at right angles to the 

layer below. If more than one person is on each 

team, team members should take turns drawing 

cards and moving blocks. If you run out of 

Game Cards, shu e the cards in the discard pile 

and use these as a new stack of Game Cards.

3. Continue playing until one team’s stack falls, 

or one team has removed all of their blocks 

from the stack. If your team is fi rst to remove 

all of the blocks from your stack—you win! If 

your stack is the fi rst to fall—you lose!

NOAA’s 

Building Blocks

What You Will Do

Play a game using blocks from 

Jenga® or Uno Stacko®. You can 

play this game by yourself, or 

with as many as eight players

3
Problem 1

You are driving from St. Louis, 

MO to Boise, ID, and need to 

know what the weather is likely 

to be along the way.

Problem 2

You are travelling through 

the midwest and want to 

see whether severe weather 

is expected during the next 

three days.

Problem 3

You just heard on the radio 

that an earthquake has been 

reported off the coast of Peru 

with a magnitude of 6.6 on 

the Richter scale. Is this likely 

to cause a tsunami on the U.S. 

Pacific coast?

Problem 5

More than 90 percent of the 

goods imported into the United 

States arrive via the oceans. 

How can ship captains obtain 

information to help them avoid 

dangerous sea conditions?

Problem 6

Over 77 million Americans 

enjoy recreational boating. 

How can these boaters keep 

track of weather that may 

affect them?

Problem 7

You just felt the earth shake! 

How can you find out if this 

is a minor tremor or a serious 

emergency?

Problem 4

 Every day, hundreds of 

private and commercial 

aircraft are in the air over 

the United States. How can 

pilots check on weather 

conditions that may affect 

the safety of their flights?

Problem 9

Intense bursts of electromagnetic radiation from the sun called 

“solar flares” can disrupt cell 

phones and GPS systems. Is there 

any way to predict when solar 

flares may happen?

Problem 10

Lightning is the second most 

frequent cause of weatherrelated deaths in the United 

States (floods are number 

one). How can you find out 

about lightning safety?

Problem 11

You are planning a boat trip 

through the Florida Keys. 

Where can you find out about 

nautical charts and other 

boating information for this 

area?

Problem 8

A railroad tank car is 

leaking chlorine gas. What 

system is in place to provide 

emergency information to 

the public?

Problem 13

You live near a marina, and 

are concerned about what 

should be done in case of an oil 

spill. Where can you get this 

information?

Problem 14 

You live near a salt marsh 

that used to be used as a local 

dump for construction debris. 

Now you and your friends 

would like to clean it up and 

restore it as a wildlife habitat? 

Who knows how to do this?

Problem 15

A ship captain entering Chesapeake Bay needs up-to-the-minute information on currents, 

tides, and water levels to be 

sure he can navigate beneath 

several bridges. Where can he 

get this information?

Problem 12

You are planning a SCUBA 

diving trip to photograph 

coral reefs with some 

friends, and want to be sure 

everyone knows how to plan 

dives and what to do in case 

of emergencies. Who has 

this information?

Photocopy this page 

and cut out the cards 

along the lines.
Problem 16

You are looking for a poster 

that shows all of Earth’s 

mountains and valleys, 

including those in the ocean. 

Where could you look?

Problem 17

You are doing a report on 

coral reefs, and need some 

great pictures of reef animals. 

Where can you find them?

Problem 18

Our nation’s coasts are being 

developed at a rapid rate. 

What can be done to protect 

special coastal areas that contain unusual marine life and 

important historical resources 

like shipwrecks?

Problem 20

In the days following Hurricane 

Sandy, rescuers desperately 

needed before-and-after aerial 

images that covered coastal areas 

affected by the storm. Who has 

these kinds of images?

Problem 21

Man Overboard! A sailor has 

fallen overboard, but no one 

noticed when the accident happened. The Coast Guard has been 

called, but how can they find him 

in hundreds of square miles of 

ocean?

Problem 22

You have just found an injured whale that seems to be 

stuck in shallow water. Who 

can you call?

Problem 19

The deep ocean contains new 

species that may provide solutions to problems such as 

energy and human disease. 

Yet, most oceans are still 

unexplored. What organization is dedicated to ocean 

exploration?

Problem 24

Many marine turtles are 

threatened by accidental capture and drowning in fishing 

gear, boat collisions, and damage to coastal beaches where 

they nest. What can be done to 

protect sea turtles?

Problem 25

Living marine resources provide 

food, employment, and recreation, 

but are threatened by overuse, 

coastal development, pollution, and 

natural disasters. How can we protect living marine resources and 

still enjoy benefits they provide?

Problem 26

You have heard that temperature changes in the Pacific 

Ocean called El Nino can have 

serious effects on your local 

weather. Where can you find 

out whether these changes are 

happening right now, or are 

expected later this year?

Problem 23

More people want to eat 

seafood, but overfishing is 

a serious problem and over 

70% of our seafood is imported. How can we increase 

our domestic seafood supply 

and still protect our seafood 

resources?

Problem 28

How can you find out how global 

climate change is likely to affect 

marine ecosystems such as coral 

reefs?

Problem 29

Hurricane Hunters fly into the 

middle of storms to provide 

information for forecasts that 

save thousands of lives. Who has 

the planes and pilots to do this 

dangerous work?

Problem 30

Your science teacher is 

fascinated by marine biology and ocean research, and 

wants to get first-hand experience with scientific research 

at sea. How can she do that?

Problem 27

You have heard that Earth’s 

climate is changing. How can 

you find out whether temperatures in the U.S. have been 

above or below normal during 

the last few years?

Photocopy this page 

and cut out the cards 

along the lines.
Solution 2

The National Weather Service 

Storm Prediction Center shows 

active storm systems over 

the 48 states, and provides 

detailed discussions of severe 

weather events at 

www.spc.noaa.gov/

Solution 3

NOAA’s Pacific Tsunami Warning 

Center and West Coast / Alaska 

Tsunami Warning Center provide 

tsunami warnings and information at

Solution 4

NOAA’s National Weather 

Service’s Aviation Digital Data 

Service provides forecasts, 

analyses, and observations of 

weather conditions that may 

affect safe aviation. 

Solution 6

The National Weather 

Service’s Marine and Coastal 

Weather Services Branch 

provides information on 

conditions on coastal waters, 

Great Lakes, and open oceans. 

Solution 8

 NOAA Weather Radio broadcasts weather forecasts, as 

well as emergency information 

about natural hazards, environmental hazards, and public 

safety (such as AMBER alerts). 

Solution 9

The National Weather Service 

Space Environment Center 

forecasts space weather caused 

by activity on the sun, such as 

solar flares.

www.swpc.noaa.gov

Solution 10

NOAA’s Lightning Safety Web 

page has handouts, safety tips, 

medical facts, survivor stories, 

photos, and much more at 

Solution 11

NOAA’s Office of Coast Survey 

provides nautical charts and 

other navigational products 

needed to safely operate marine 

vessels.

Solution 12

The NOAA Dive Manual is an 

encyclopedia of diving which 

includes information about 

dive planning, operations, and 

emergencies.

Solution 13

NOAA’s Office of Response 

and Restoration provides 

information and solutions 

for environmental hazards 

from oil, chemicals, and 

marine debris.

Solution 14

 NOAA’s Office of Response 

and Restoration offers case 

studies, planning tools, 

and technical assistance to 

projects that restore and 

monitor coastal and estuary 

habitats.

Solution 15

NOAA’s Tides and Currents 

Web site provides real-time 

and historical information on tides, water levels, 

currents, and weather in 

ports and major waterways 

throughout the U.S.

Solution 5

The National Weather 

Service’s Marine and Coastal 

Weather Services Branch provides information on coastal 

waters, Great Lakes, and open 

oceans. 

Solution 7

NOAA Weather Radio broadcasts weather forecasts, 

and emergency information about natural hazards, 

environmental hazards, 

and public safety (such as 

AMBER alerts). 

Solution 1

NOAA’s National Weather 

Service provides immediate 

access to all forecasts for the 

entire United States at 

www.weather.gov/

www.nws.noaa.gov/om/marine/home.

htm

www.nws.noaa.gov/om/marine/

home.htm www.nws.noaa.gov/nwr

www.ptwc.weather.gov www.aviationweather.gov

www.nws.noaa.gov/nwr/

www.lightningsafety.noaa.gov http://charts.noaa.gov/

www.response.restoration.noaa.gov www.response.restoration.noaa.gov www.tidesandcurrents.noaa.gov

Photocopy this page 

and cut out the cards 

along the lines.

www.omao.noaa.gov/learn/diving-program/diving
Solution 16

NOAA’s National Geophysical 

Data Center provides maps, 

posters, data, and images of 

many different features on 

Earth’s surface. 

Solution 17

NOAA’s Photo Library has 

thousands of images of marine 

species, shorelines, weather and 

space; from coral reefs to the 

South Pole, from great whales 

to microscopic bacteria.

Solution 18

 NOAA’s Office of National 

Marine Sanctuaries includes a 

network of underwater parks 

where natural and cultural 

resources are protected while 

still allowing people to use and 

enjoy them.

Solution 19

NOAA’s Office of Ocean 

Exploration coordinates 

expeditions to explore Earth’s 

“final frontier.” Expeditions 

take place around the world, 

but are concentrated in U.S. 

waters. 

Solution 20

NOAA’s National Geodetic 

Survey has provided high-resolution aerial photography of 

the 95,000-mile U.S. shoreline 

since the 1930’s. 

Solution 21

NOAA operates the Search & 

Rescue Satellite Aided Tracking 

System to locate people in distress 

almost anywhere in the world at 

anytime and in most conditions.

www.sarsat.noaa.gov

Solution 22

NOAA’s National Marine 

Fisheries Service coordinates 

volunteer marine mammal 

stranding networks in all 

coastal states that include 

whale rescue teams. 

Solution 23

NOAA Fisheries’ Aquaculture 

Program develops ways to farm 

marine animals to provide more 

seafood, boost commercial and 

recreational fishing and restore 

some endangered species.

Solution 24

NOAA’s National Marine 

Fisheries Service and the 

U.S. Fish and Wildlife Service have developed ways 

to protect and restore sea 

turtle populations.

Solution 25

NOAA Fisheries’ Office of 

Sustainable Fisheries works 

to maintain healthy fishery 

stocks, eliminate overfishing, 

rebuild overfished stocks, and 

increase benefits from living 

marine resources.

Solution 26

NOAA’s National Weather Service 

Climate Prediction Center forecasts short-term events such as 

El Nino, and provides information 

about possible risks of extreme 

weather events.

Solution 27

NOAA’s Climate Program 

Office provides current and 

historical information on 

whether temperatures in 

the U.S. are above or below 

normal.

Solution 28

NOAA’s Climate and Ecosystems Program is dedicated to 

understanding and predicting the effects of climate 

variability and change on 

marine ecosystems.

Solution 29

NOAA’s Office of Marine and 

Aviation Operations has a fleet 

of aircraft that operate in 

extreme conditions, and have 

the only pilots in the world 

qualified to fly into hurricanes 

at low altitudes.

Solution 30

NOAA’s Teacher at Sea Program provides opportunities 

for teachers to do scientific 

research aboard its ships and 

share that experience with 

students and colleagues. 

www.ngdc.noaa.gov/ www.photolib.noaa.gov

www.oceanexplorer.noaa.gov

www.oceanservice.noaa.gov/geodesy/aerialphotoswww.nmfs.noaa.gov/aquaculture

www.nmfs.noaa.gov/pr/species/turtles www.nmfs.noaa.gov/sfa www.cpc.ncep.noaa.gov/ www.ncdc.noaa.gov

www.cpo.noaa.gov

www.omao.noaa.gov

www.sanctuaries.noaa.gov

www.fisheries.noaa.gov/pr/health/report.htm

www.teacheratsea.noaa.gov/

Photocopy this page 

and cut out the cards 

along the lines.
noaa.gov

Discover Your World With NOAA

8

E

xploration is an important part of 

NOAA’s focus on Earth’s ecosystems. 

Ocean exploration in the United States 

began in 1807 when Thomas Jeff erson 

authorized the Survey of the Coast. 

But today, after 200 years, about 95% 

of Earth’s oceans are still unexplored—

mainly because we haven’t known how 

to handle the extreme cold and pressure of the deep ocean until very recently. Through NOAA’s Offi ce of Ocean 

Exploration and Research, modern pioneers are investigating parts of Earth’s 

underwater world that have been virtually unknown and unseen. Such exploration may reveal clues to the origin of 

life on Earth, cures for human diseases, 

answers on how to achieve sustainable 

use of resources, links to our maritime 

history, and information to protect 

endangered marine species.

An exciting new project, the Global 

Earth Observation System (GOES), 

tells us a lot about the Earth and how 

it works. The basic idea is to combine 

information from thousands of sources 

that are already making observations 

about Earth to make people around 

the globe healthier, safer, and better 

equipped to manage basic daily needs. 

NOAA has partnered with more than 60 

countries and the European Commission to make this idea a reality.

Learn more about NOAA’s Exploration 

projects with these activities:

• Build an Underwater Robot

• Make Your Own Volcano

• Weird, Red, and Slightly Gross

• Do You Have Twisted Vision?

• Be A Shipwreck Detective! 

and more!

Explore the Earth

Taking the pulse of the planet... king the pulse of the planet... Courtesy NOAA

Courtesy OAR/NURP

Courtesy NOAA Courtesy NOAA

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA
National Oceanic and Atmospheric Administration (NOAA) 9

EXPLORE THE EARTH

Boat Building Challenge

Who were the fi rst boat-builders?

No one really knows.

The oldest known boats are dugout canoes constructed in China and South 

Korea around 6,000 B.C. But it’s possible that the almost-human species 

Homo erectus used some type of boat 800,000 years ago!

Since H. erectus are known to have made tools from bamboo, they may 

also have made rafts from the same material. But regardless of the 

materials and who used them, the basic principles that allowed the fi rst 

boats to fl oat are the same principles that operate on the most modern 

supertanker.

Egyptian tomb painting from 1450 B.C. showing offi cer with sounding pole. Offi cer is telling crew to 

come ahead slow. Engineers with cat-o’-nine-tails assure proper response from the “engines.” 

Courtesy NOAA.

What You Will Do

Design a boat hull that is able to 

float a specified weight. 

Then, design a way to propel your vessel 

using wind power

What You Will Need

❒ Sheets of aluminum foil, 12 inches x 12 inches; one sheet for each hull

❒ 50 pennies for each hull

❒ Plastic or metal tub full of water, at least 24 inches diameter

❒ Foam plates

❒ Wooden skewers

❒ Poster board

❒ Hole punch

❒ Battery operated fan

❒ Masking tape

❒ Modeling clay

SCIENCE | Service | Stewardship
noaa.gov

Discover Your World With NOAA

10

• Cut a sail out of heavy paper, and use the 

punch to make holes for the mast (wooden skewer).

• Use masking tape and/or modeling clay to 

help hold the mast onto the hull.

• To waterproof your boat, place it on top of a 

piece of aluminum foil, then fold the foil 

up and over the sides of the boat as shown 

below. 

How to Do It

1. Fold a sheet of aluminum foil into a shape that 

will fl oat in the tub of water and support 

the weight of ten pennies. Not sure how to 

do this? Read “What’s Happening” for some 

clues.

2. Use another sheet of aluminum foil, pieces 

of foam plate, wooden skewers, and poster 

board to make a boat that will use sail power 

to carry ten pennies across the tub of water. 

The drawing below shows one way to cut 

and fold a piece of poster board to make a 

three-dimensional boat.

• Use masking tape at the corners of the bow 

(front of the boat) and stern (rear of the 

boat).

• Make a keel by pinching the aluminum foil to 

form a ridge that runs from front to back 

along the middle of the bottom of the 

boat. (See illustration below left.)

3. Now let’s go for a sail! Place ten pennies in 

the boat, fl oat the boat in a container of 

water, and use the fan as a source of wind to 

sail your vessel around the container.

 Note: The pennies perform an essential function for sailing vessels: they provide weight 

in the hull, called “ballast,” that keeps the 

boat from turning over when the wind presses against the sails.

Want to Do More?

Have a contest to see who can build a hull that 

will carry the most “cargo” (the greatest number 

of pennies), starting with the same materials. 

You can modify the contest to see whose can 

build the fastest sailing boat. You may want to 

experiment to fi nd out whether it is better to use 

one large sail or several small sails to increase 

sailing speed, and whether triangular shaped 

sails or square sails give the best performance.

What’s Happening?

Water tends to maintain a level surface. When 

you put an object into water, gravity pulls the 

object down and displaces some of the water, 

which means some of the water is pushed aside. 

Aluminum foil
National Oceanic and Atmospheric Administration (NOAA) 11

SCIENCE | Service | Stewardship Explore the Earth

Now the surface of the water is no longer level. 

Gravity pulls the displaced water down, and 

causes an upward force on the object. This 

upward force is equal to the weight of the water 

that the object displaces, and is called buoyancy. 

Buoyancy depends upon the volume of liquid 

displaced as well as the density of the liquid. 

Density is the mass of a certain volume of liquid, 

usually stated as grams per milliliter. This is why 

it is easier to float in the ocean than in fresh 

water. Seawater is more dense than fresh water, 

so your buoyancy is greater in the ocean.

The amount of fluid that an object displaces 

depends upon the volume of the object:

more volume means more fluid displaced, which 

means more buoyancy. Increasing the volume of 

an object also increases its surface area, which in 

turn increases the effect of friction as the object 

moves through the fluid. Boat designers have to 

consider buoyancy as well as friction when deciding on the shape of a boat’s hull. A boat designed 

for speed must have enough displacement to 

stay afloat, but surface area has to be minimized 

to decrease the effects of friction. On the other 

hand, an object designed to carry a heavy weight, 

such as a cargo ship, must be designed with 

greater displacement, as well as greater power to 

overcome the effects of increased friction.

Boat hulls are designed to displace a volume of 

water that weighs more than the boat and its cargo. If the force of displaced water pushing on the 

hull is greater than the force of gravity pulling the 

boat down, then the boat floats! But if you could 

take a sea-worthy boat hull, break it down, and 

bundle the pieces together, the bundle will sink. 

Why? Because there is no longer sufficient water 

displacement to counteract the force of gravity on 

the pieces of the hull.

Visit www.sedl.org/scimath/compass/v02n03/

boat.html and

www.thirteen.org/edonline/nttidb/lessons/jx/

buoyjx.html for more boat building challenge 

ideas.

The idea of buoyancy was summed up by a Greek 

mathematician named Archimedes: any object, wholly 

or partly immersed in a fluid, is buoyed up by a force 

equal to the weight of the fluid displaced by the 

object. Today, this definition is called the Archimedes 

Principle.

Archimedes is considered one of the three greatest 

mathematicians of all time. The other two are Newton and Gauss. Archimedes was born in 287 B.C., in 

Syracuse, Greece. He was a master at mathematics and 

spent most of his time thinking about new problems 

to solve.

Many of these problems came from Hiero, the king of 

Syracuse. Archimedes came up with his famous principle while trying to solve this problem.

The king ordered a gold crown and gave the goldsmith 

the exact amount of metal to make it. When Hiero 

received it, the crown had the correct weight but the 

king suspected that some silver had been substituted 

for the gold. He did not know how to prove it, so he 

asked Archimedes for help. 

One day while thinking this over, Archimedes went for 

a bath and water overflowed the tub. He recognized 

that there was a relationship between the amount of 

water that overflowed the tub and the amount of his 

body that was submerged. This observation gave him 

the means to solve the problem. He was so excited 

that he ran naked through the streets of Syracuse 

shouting “I have found it!”. The goldsmith was 

brought to justice and Archimedes never took another 

bath...(just kidding!).

The Archimedes Principle

Portrait of Archimedes, by Domenico Fetti, about 1620

ww
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12

Make Your Own Astrolabe

The mariner’s astrolabe is an ancient 

navigation instrument for measuring celestial 

altitude (celestial altitude is the “height” of 

a star, planet or other celestial object above 

the horizon). Celestial altitude is important to 

mariners, because it provides a way to estimate 

geographic latitude, which is a location’s 

distance from the equator. Astrolabes were 

the most popular astronomical instrument 

for several centuries, but they eventually were 

replaced by quadrants, which today have been 

replaced by sextants.

What You Will Do

Make your own astrolabe, and 

use it to estimate 

the height of a tree, building, 

or other vertical object

What You Will Need

❒ Stiff cardboard, fi le folder, or wood, approximately 8 inches square

❒ Tools for cutting the cardboard or wood

❒ Glue

❒ Drill with a 3/16 inch drill bit

❒ #8 Round head bolt (long enough to go 

through both pieces of the astrolabe), #8 

nut, and three #8 washers

❒ Rope, string, or twine, about 12 inches long 

(the diameter of the rope isn’t very important; about 1/8 inch is ideal)

Warnings

1. Drills and cutting tools are sharp! Get help 

from an adult and be careful! 

2. Power saw blades and drill bits can shatter 

or throw scraps at high speed, possibly 

causing serious injury. Be sure to wear eye 

protection and follow other recommended 

safety precautions before using any power 

tools!

A mariner using a descendant of the astrolabe called 

an “octant.” Courtesy NOAA
National Oceanic and Atmospheric Administration (NOAA) 13

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How to Do It

Optional: Before you start, you may want to search the internet for images 

of astrolabes (there are thousands!).

1. Glue the “Astrolabe Template” onto a piece of wood or stiff cardboard. With 

help from an adult, cut out the two pieces of the astrolabe as closely to 

the lines as possible. It isn’t essential to cut out the four pie-shaped pieces in the middle of the astrolabe, but it will be more authentic if you do 

(mariner’s astrolabes had these pieces cut out to reduce wind resistance 

when the instrument was being used on ships). 

2. Drill a 3/16 inch diameter hole through the center of the astrolabe and 

sight vane. Assemble the two pieces with a #8 bolt, nut, and three 

washers (one washer under the head of the bolt, one between two 

astrolabe pieces, and one under the nut).

90 10

20

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80 90

10

20

30

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10 90

20

30

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Astrolabe Template

Sight Vane
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14

3. Tie a loop of rope, string, or twine through the 

hole at the top of the astrolabe.

4. To use your astrolabe, hold the instrument 

by the rope so that it hangs vertically. Line 

up the two ends of the sighting vane with 

the top of the object whose height you are 

measuring. Read the altitude of the object 

in degrees from the upper left or lower right 

scale on the astrolabe.

 [NOTE: Notice that a horizontal object measures 90° on the upper left and lower right 

scales. This measurement is called “zenith 

distance” and is used on a mariner’s astrolabe to simplify latitude calculations.]

5. To fi nd the height of a vertical object using 

your astrolabe: 

a. Set the sight vane to 45° on the upper left 

or lower right scale.

b. Hold the astrolabe so that it hangs 

vertically, and walk to a position at which 

the top of the object you want to measure 

is lined up with the two ends of the sight 

vane. Measure the height of the astrolabe 

above the ground.

c. Measure or pace the distance to the base of 

the object. Add this distance to the height 

of the astrolabe above the ground. The 

sum is equal to the height of the object.

 Knowing the length of your pace can be useful for many things. Back in the day, a pace 

meant the distance traveled when you took 

TWO steps. For most people, this works out to 

be about 5.25 feet. So 1,000 paces is about 

equal to one mile. Find the length of your 

pace by walking 20 steps and measuring the 

distance covered. This distance divided by 10 

is the length of your pace.

Want to Do More?

1. Check out www.astrolabes.org/ for examples 

of astrolabes made by individuals. You may 

also want to watch the NOVA program, Lost 

at Sea: The Search for Longitude (available 

from public libraries and from www.pbs.org/

wgbh/nova/novastore.html).

2. Sometimes you won’t be able to get far enough 

away from an object to line up the ends of 

the sight vane when it is set to 45°. You can 

still use the astrolabe to fi nd height, but 

will have to use a little trigonometry (don’t 

worry, it isn’t really very hard). Here are the 

basic things you need to know:

a. A “right triangle” has two sides that meet 

at an angle of 90°. 

b. The side of the triangle opposite the 90° 

angle is called the hypotenuse. 

45°

45°
National Oceanic and Atmospheric Administration (NOAA) 15

SCIENCE | Service | Stewardship EXPLORE THE EARTH

c. The tangent of one of the other angles is 

defi ned as the length of the side opposite 

the angle divided by the side closest to 

the angle (NOT the hypotenuse).

So, in the drawing below, the tangent of angle a 

is equal to side A divided by side B. A shorthand 

way to write the last sentence is:

tan a = A ÷ B

Now, we can fi nd the height of the fl agpole in the 

drawing to the right.

The height of the fl agpole is side A plus “H” 

which is the height of your eyeball above the 

ground. 

The tangent of angle a is equal to side A divided 

by side B. Written in the shorthand way:

tan a = A ÷ B

Suppose angle a is equal to 60° and side B is 50 

feet. Then,

tan 60° = A ÷ 50 feet

You can fi nd tangents on many calculators, and 

in tables from trigonometry books and on the 

internet. The tangent of 60° is 1.73. So,

1.73 = A ÷ 50 feet

So, A is equal to 1.73 multiplied by 50, which is 

86.5 feet

The height of the fl agpole is side A plus “H” 

which is the height of your eyeball above the 

ground. If H is equal to 4.5 feet, the height of the 

fl agpole is: 

86.5 ft + 4.5 ft = 91 feet

a

A

B

hypotenuse

right angle

A

a

B

Using Trigonometry and Your Astrolabe to Find the Height of an Object

H
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16

“When neither sun nor stars appeared for many a day, they 

gave up hope. This was a terrible handicap to them because 

these ancient navigators had no compass nor any other instrument. The only way they could guide the ship was by the sun 

and stars. When they could not see them for many days they 

lost all knowledge of their whereabouts. They were drifting 

helplessly before a howling gale in the midst of a turbulent sea 

with no idea where they were headed.”

~ from God and Shipwrecks by Ray C. Stedman

www.raystedman.org/new-testament/acts/god-and-shipwrecks

One of the most important improvements to ocean navigation was the 

invention of the compass. There is some disagreement about who should 

get credit for this invention. It’s pretty clear that the Chinese knew about 

magnetism as early as 2637 BC, but the fi rst written description of a 

compass for navigation didn’t appear in Europe until 1190. Why did it 

take so long? After you do this activity, you may have at least one good 

answer!

North Pacifi c storm waves as seen from the M/V NOBLE STAR, Courtesy NOAA

What You Will Do Make a simple compass to find magnetic north or 

south, depending on where you live

Make Your Own Compass

What You Will Need

❒ Sewing needle about one to two inches long

❒ Small bar magnet or refrigerator magnet

❒ A small piece of cork (corks from wine bottles work well, but not the 

plastic stoppers)

❒ A small glass or cup of water to fl oat the cork and needle 

❒ Pair of pliers
National Oceanic and Atmospheric Administration (NOAA) 17

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Warnings

1. Needles are sharp. Be careful!

2. Magnets can damage cards with a magnetic 

stripe (credit cards, library cards, school IDs, 

etc), floppy disks, and some electronic devices. Keep magnets away from these things.

How to Do It

1. Rub a magnet over the needle a few times, 

always in the same direction. This action 

magnetizes the needle. 

2. Cut off a small circle from one end of the cork, 

about 1/4-inch thick. Lay the circle on a flat 

surface. 

3. Using a pair of pliers, carefully poke the 

needle into one edge of the circle and force 

the needle through the cork so that the end 

comes out the other side. Push the needle 

far enough through the cork so that about 

the same amount of needle is sticking out 

each side of the cork. Be careful not to stick 

yourself! 

4. Fill the glass or cup about half full of water, 

and put the cork and needle assembly on the 

surface of the water. 

5. Place your “compass” on a flat surface and 

watch what happens. The needle should 

point towards the nearest magnetic pole —

north or south, depending upon where you 

live.

6. Try placing a magnet near your compass and 

watch what happens. How close does the 

magnet have to be to cause any effects? Try 

this again with a nail or other steel object. 

You can see why it’s important to keep metal 

objects away from compasses on ships!

7. Imagine you are on the deck of a ship tossing 

back and forth on the open ocean. How well 

do you think your compass would work? When 

the cork floats on the water it creates a sort 

of low-friction bearing. This kind of bearing 

is essential to allow the needle to rotate in 

response to Earth’s magnetic field. But a cup 

of water probably wouldn’t last long on the 

deck of a rolling ship! The need for a sturdy 

low-friction bearing was one of the reasons 

that it took a long time for mariners to use 

compasses at sea, even though the basic 

principles had been known for centuries.

What’s Happening

Magnetic fields are areas that contain a force 

created by moving electrical charges. Earth 

produces a magnetic field. This field is very weak, 

but it is sufficient to align magnetized objects—

such as your needle—that are free to rotate. By 

floating the needle on the cork, you allow it to 

rotate freely so the needle becomes lined up with 

Earth’s magnetic field, and points toward the 

north or south pole of the planet.

Needle

Magnet

“Compass”

Cup or glass half-filled with water
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18

Tied Up In Knots

“Topmen, aloft!” sang out the commodore in a piercing 

voice that rose above the screaming wind and roar of 

the sea. “Take in the topgallants and royals!”

We all raced aloft; but no sooner had these sails 

been furled and we returned to the deck than the 

commodore was at us again.

“Reef topsails!” he shouted even louder than before. 

“Away aloft—take in one reef!”

Mick and I scrambled up, almost out of breath, into 

the mizzen-top; which we hardly reached before we 

heard the commodore give the next order necessary to 

enable us to take in the reef—

“Weather topsail braces, round in! Lower the 

topsails!”

~ from Young Tom Bowling by J.C. Hutcheson, 1896. 

Do you know how to tie a reef knot? A sailor’s life and the safety of 

the entire crew and ship can depend on the quality of knots he ties. 

Sailors take pride in being able to match the right knot to a specifi c 

job, and even modern sailors need to master this skill. 

Tied Up In Knots

“In the rigging”. In The South Pole, by Roald Amundsen, 1872-1928. 

Archival Photograph by Mr. Steve Nicklas, NOS, NGS. Courtesy NOAA

What You Will Do

Learn to tie some basic knots that have been 

used by mariners for centuries and are often 

useful in everyday life
National Oceanic and Atmospheric Administration (NOAA) 19

SCIENCE | Service | Stewardship Explore the Earth

What You Will Need

r One or more pieces of rope, about 3 feet long; 

nylon, polypropylene, manila, or cotton 

ropes, 1/4-inch to 1/2-inch in diameter work 

well

r Pictures or video showing how to tie knots

How to do It

There are three different types of “knot.” 

• A Bend is used to join two ropes (often of 

different diameters), or to fasten a rope to 

an eye, ring, or other structure. Examples: 

sheet or becket bend; anchor bend

• A Hitch is designed to stay in place under 

strain, but remain easily adjustable when 

the strain is removed. Examples; clove 

hitch, half hitch, rolling hitch

• A Knot is used to fasten ropes together, 

or to fasten a rope to an object, or to 

enlarge the end of a rope (as in a stopper 

knot.) A stopper knot is usually tied at 

the end of a rope to prevent the line from 

slipping through an eye, ring, or pulley. 

A good knot must be able to be easily 

untied. Examples; bowline, reef (square) 

knot, overhand knot, figure eight knot

Five Useful Knots

Bowline

Uses: Forms a loop at the end of a rope that 

will not slip (close up) when the rope is under 

tension. This knot is easy to untie, even after 

it has been under high strain.

How to Tie It: Be sure the free end of the rope 

lies inside the loop when the knot is completed.

Figure Eight

Uses: A “stopper” used to prevent the end of 

the rope from slipping through a pulley. Also 

used in mountain climbing to secure a rappelling line to a climbing harness.

How to Tie It:
noaa.gov

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20

Clove Hitch

Uses: Used to secure a line to a round object 

such as a post or rail. 

How to Tie It:

Reef Knot (Square Knot)

Uses: Used for lashings and other situations 

where a line must be tied around an object, 

but should NEVER be used as a bend to tie 

two ropes together. “Reefing” a sail means to 

make the sail smaller by partially folding or 

“furling” the sail. A Reef Knot is used to tie 

the sail in a partially folded position.

How to Tie It: If you grab one of the free ends 

and jerk it across the knot, the knot will “capsize” and slip apart easily.

Sheet Bend

Uses: One of the best bends for joining two 

ropes together, especially if the ropes do not 

have the same diameter.

How to Tie It: The rope with the larger diameter should be used for the loop. 
National Oceanic and Atmospheric Administration (NOAA) 21

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Turn Your Knot Tying Skill into a Game:

Organize a knot tying race. Give each contestant five pieces of rope, and see 

who will be first to correctly tie all five knots. If one knot is wrong, the contestant loses. If this seems harsh, remember that a single badly tied knot 

can be disaster for mariners at sea.

Want to Know More?

There are lots of books on knot tying and ropecraft. Two very good ones are:

Knotcraft: The Practical and Entertaining Art of Knot Tying by Allan and Paulette Macfarlan; Dover Craft Books, 1983

The Arts of the Sailor – Knotting, Splicing and Ropework by Hervey Garret 

Smith; Dover Publications, reprint edition

You can find animated knot tying instructions at 

www.animatedknots.com/indexbasics.php

Another Web site with instructions for tying many different knots is: 

www.2020site.org/knots/

 The dredging and sounding arrangements on board the CHALLENGER.

 In The Voyage of the CHALLENGER - The Atlantic Vol I, by Sir C. Wyville Thomson, 1878. 

 Archival Photography by Steve Nicklas, NOS, NGS. Courtesy NOAA
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22

“The Gallant Frigate Amphitrite, she lay in Plymouth sound;

Blue Peter on the foremast peak for we were outward bound.

We were waiting there for orders to send us far from home;

When the orders came for Rio, and then around Cape Horn.”

~ from The Gallant Frigate Amphitrite, a traditional sea shanty

(This tune is available in MIDI format at 

www.traditionalmusic.co.uk/song-midis/Rounding_the_Horn.htm)

Who’s Blue Peter? Who—or what—do you think Blue Peter is?

Traditionally, Blue Peter is the nickname given to the nautical signal fl ag 

that represents the letter “P.” When communicating with signal fl ags, 

each letter of the alphabet has a specifi c meaning. The letter “P” means 

“All persons should report on board as the vessel is about to proceed to 

sea.” So when a ship is fl ying Blue Peter, everyone knows that its voyage 

is about to begin.

International code fl ags are still used to communicate between ships 

and between ship and shore. The colors used on nautical signal fl ags are 

chosen because red, blue, yellow, black, and white are colors that can 

be most easily distinguished at sea. Signals may use one or more fl ags 

to communicate a particular message. One-fl ag signals are used for very 

urgent or very common signals.

Two-fl ag signals are used to provide more specifi c information, 

particularly in emergency situations or when maneuvering a vessel. 

Three-, four-, fi ve-, six-, and even seven-fl ag signals are used to convey 

other types of information. Sometimes, when a “standard” signal won’t 

work, fl ags may be used to spell out individual words.

The CHALLENGER at St. Paul’s Rocks. In The Voyage of the CHALLENGER - The Atlantic Vol I, by 

Sir C. Wyville Thomson, 1878. Archival Photography by Steve Nicklas, NOS, NGS. Courtesy NOAA

What You Will Do

Make a set of nautical signal flags, 

and use the flags to send messages
National Oceanic and Atmospheric Administration (NOAA) 23

SCIENCE | Service | Stewardship Explore the Earth

What You Will Need

r White poster board or white cloth

r Colored markers

r Two pieces of string or light rope (1/8-inch 

diameter or less), long enough to loop over 

a tree limb or other object that will allow you 

to hoist your flags

r One or two copies of “Table of Single Letter 

Signals”

r Scissors to cut poster board or cloth

r Ruler and compass (or round object such as a 

bowl or can)

r Note pads and pencils

How to Do It

1. Cut out 26 rectangular pieces of poster board 

or cloth, about 8 inches x 10 inches. Cut one 

triangular pennant, shaped like this:

4. Make holes in the left side of your flags to 

attach the string or rope.

5. Loop the strings or ropes over tree limbs or 

other objects that will allow you to raise and 

lower your flags.

6. If you have four or more people, you can have 

a competition. Each team should have a 

signalling crew and a receiving crew at least 

20 feet away. Each crew should have a string 

or rope (called a “halyard”) looped over a 

tree limb or other object that will allow the 

crew to hoist their signals. The signalling 

crew should have a complete set of alphabet 

flags, and the receiving crew should have an 

answering pennant.

Each team should make a list of ten messages using the “Table of Single Letter Signals,” 

then give their list to the other team’s 

signalling crew. The receiving crews are not 

allowed to look at the lists!

7. On the “Go” signal, each signalling crew raises 

the flag corresponding to the first message 

on their list. As soon as the receiving crew 

understands the message, they should write 

the message on a note pad and raise their 

answering pennant. Then the receiving crew 

lowers their flag, and replaces it with the 

flag for the next message.

When the receiving crew understands a 

signal, they hoist their answering pennant as 

far up as the halyards will go. At this point, 

the pennant is said to be “close up.” Then, 

when the signalling crew lowers their signal, 

the receiving crew lowers their pennant 

about halfway down. Now the pennant is said 

to be “at the dip,” and is held in this position 

until the next signal is understood.

The first team to correctly send all ten messages wins!

Want to Do More?

1. You can download the entire International 

Code of Signals from www.seasources.net/

PDF/PUB102.pdf

2. See www.marinewaypoints.com/learn/flagtrans/flags.shtml for a Web page that automatically translates text into flag signals.

5”

12.5”

1 3/8”

2. Use your ruler and compass (or round object) 

to draw the shapes needed for each flag 

shown in the “Nautical Signal Flags” illustration.

3. Use markers to color your flags as shown in 

the illustration.
noaa.gov

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24

A I have a diver down; keep well clear at slow 

speed. 

B I am taking in, or discharging, or carrying 

dangerous goods. 

C Yes 

D Keep clear of me; I am maneuvering with 

difficulty. 

E I am altering my course to starboard. 

F I am disabled; communicate with me. 

G I require a pilot. When made by fishing vessels, this signal means “I am hauling nets”. 

H I have a pilot on board. 

I I am altering my course to port. 

J I am on fire and have dangerous cargo on 

board: keep well clear of me, or I am leaking 

dangerous cargo. 

K I wish to communicate with you. 

L You should stop your vessel instantly. 

M My vessel is stopped and making no way 

through the water. 

N No

O Man overboard. 

P All persons should report on board as the 

vessel is about to proceed to sea. 

Q My vessel is “healthy” and I request permission to proceed into port. 

S I am operating astern propulsion. 

T Keep clear of me; I am engaged in pair trawling. 

U You are running into danger. 

V I require assistance. 

W I require medical assistance. 

X Stop carrying out your intentions and watch 

for my signals. 

Y I am dragging my anchor. 

Z I require a tug.

Single Letter Signals

A

Alfa

B

Bravo

C

Charlie

D

Delta

E

Echo

F

Foxtrot

G

Golf

H

Hotel

I

India

J

Juliet

K

Kilo

L

Lima

M

Mike

N

November

O

Oscar

P

Papa

Q

Quebec

R

Romeo

S

Sierra

T

Tango

U

Uniform

V

Victor

W

Whiskey

X

X-ray

Y

Yankee

Z

Zulu

Answer
National Oceanic and Atmospheric Administration (NOAA) 25

SCIENCE | Service | Stewardship EXPLORE THE EARTH

“At about 9 p.m., I felt the vessel graze the bottom... 

I grabbed my cap, and rushed up the steps leading to 

the spar deck...and immediately afterward heard the most 

dreadful and agonizing sounds as the ship hurled herself 

on the reef...The call of the boatswain: ‘All hands prepare to abandon ship,’ I heard above all of this din. I 

could hardly walk the decks; the pounding and jumping of 

the ship swaying me from side to side.”

~ from Capt. R. O. Crisp on the loss of the revenue cutter Tahoma after hitting an uncharted reef 

on the south side of the Aleutian Islands, Alaska on September 20, 1914

(www.uscg.mil/history/webcutters/Tahoma_1909.asp)

If Alaska had been a U.S. state in 1914, the reef that wrecked the Tahoma might 

have been on Captain Crisp’s navigation charts. This is because more than a 

hundred years earlier, in 1807, President Thomas Jeff erson established the Survey of the Coast to chart the U.S. coastline to make the coasts of our nation safe 

for navigation. A top priority of the Coast Survey was (and is) to create charts 

that show the shape of the coasts, currents, and the depth of coastal waters. 

Gathering information needed for these charts is called “hydrography,” and 

people who do this work are known as “hydrographers” (“hydro” means water, 

and “grapher” is one who writes).

Today, hydrographers working for NOAA’s Offi ce of 

Coast Survey continue the work begun by the Survey 

of the Coast. These scientifi c nomads travel around 

the coasts collecting information needed for upto-date charts that guide ships in and out of U.S. 

ports. The most basic job of hydrographers is taking 

measurements of water depth (called “soundings”). 

Sounding party off USCS Brig FAUNTLEROY. 1857-Earliest picture of Coast Survey sounding 

operations. Watercolor by James Madison Alden, nephew of Lieutenant Commanding James Alden.

What You Will Do

Make a sounding box and 

discover the profile 

of a model seafloor

The Water Writers

Courtesy NOAA

Sounding party off USCS Brig FAUNTLEROY. 1857-Earliest picture of Coast Survey sounding 

Modern hydrographers use sidescan and multibeam sonar and satellite-based 

global positioning systems (GPS) to produce very detailed pictures of the sea 

fl oor. For many years though, hydrographers used lead lines to make depth 

measurements. A lead line is a rope or line with a 10-pound lead weight 

attached to the end. The hydrographer lowers the line into the water until the 

weight reaches the bottom. Markings on the line show how much line has been 

let out, which is equal to the depth of the water. Depth soundings made with 

lead lines are accurate, but they take a lot of time and only give information 

about single points of the sea bottom—so many lead line measurements are 

needed to accurately survey a given area. 

Here’s a way to get a feel for hydrographic surveying 

with a lead line—and you don’t even have to get your 

feet wet!
noaa.gov

Discover Your World With NOAA

26

What You Will Need

This activity is most challenging if you have one 

or more friends who also make a sounding box 

and set up a model seafl oor inside the box. Then 

you can trade sounding boxes and compete to 

see who can discover everything on an unknown 

seafl oor.

For each sounding box you will need:

❒ A shoebox or other cardboard box that is about 

2 inches to 4 inches high

❒ A replaceable air conditioner fi lter large 

enough to cover the box

❒ A wooden skewer about 4 inches longer than 

the height of the sounding box

❒ A ruler

❒ A felt tip marker

❒ A copy of the “Sounding Box Plotting Sheet”

❒ A pencil 

❒ Small objects such as Lego® blocks, toy vehicles, rocks, modeling clay, etc. 

❒ Masking tape 

❒ Rubber cement

How to Do It

1. Use masking tape or rubber cement to fasten 

small objects to the inside bottom of the 

cardboard box. 

2. Mark the sides of the air conditioner fi lter at 

1/2-inch intervals as shown in the “Air Conditioner Filter Grid” drawing. 

 Label the horizontal lines with numbers, and 

vertical lines with letters as shown.

3. Mark your wooden skewer every 1/4-inch with 

a felt-tip marker. If you have colored markers, you can use a diff erent color to mark 

one-inch and two-inch intervals as shown 

on the “Sounding Skewer Marking” diagram. 

This makes it easier to tell how deep the 

skewer is when you take “soundings.”

4. Fasten the air conditioner fi lter to the cardboard box with masking tape so no one can 

see inside the box.

5. Now it’s time to be a hydrographer! Use a ruler 

and the grid on the air conditioner fi lter to 

locate specifi c spots for “soundings.” Take 

“soundings” by gently pushing the skewer 

through the air conditioner fi lter until the 

skewer hits bottom. Read the “depth” on 

the skewer, and record this measurement 

in the place on the “Sounding Box Plotting 

Sheet” that matches the sampling location 

on the air conditioner fi lter grid. For example, the red star on the “Sounding Box 

Plotting Sheet” matches the location of the 

red star on the “Air Conditioner Filter Grid” 

drawing. If your sounding box is less than 10 

inches x 10 inches, you won’t use all of the 

grid squares. If it is larger than 10 inches x 

10 inches, add more horizontal and vertical 

lines to the Plotting Sheet.

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National Oceanic and Atmospheric Administration (NOAA) 27

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6. Continue making soundings until you think 

you have a clear picture of the model seafloor. Outline the features of the model 

seafloor on the Plotting Sheet, then remove 

the filter from the top of the box and see how 

well your Plotting Sheet compares with the 

actual “seafloor.”

Want to Do More?

Check out these books at the library:

The Coast Mappers by Taylor Morrison

Mapping the Seas by Walter Oleksy

Maps and Globes by Harriet Barton

The Story of Maps and Navigation (Signs of the 

Times) by Anita Ganeri 

Small Worlds: Maps and Map Making by Karen 

Romano Young 

You may also want to visit these Web sites:

 NOAA’s Office of Coast Survey homepage: 

nauticalcharts.noaa.gov

NOS’s hydrographic survey page: oceanservice.

noaa.gov/facts/hydrography.html

 Take a look at historical maps and charts: www.

nauticalcharts.noaa.gov/csdl/ctp/abstract.

htm

Try a nautical chart scavenger hunt! 

oceanservice.noaa.gov/education/nautical_

charts/scavengerhunt.html

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Nautical Chart Challenge

For as long as anyone in his family could remember, 

Francis Beaufort wanted to make scientific observations 

from the deck of a ship. In 1789 at the age of fourteen, 

he set sail as a sort of officer-in-training aboard the 

Vansittart, an East India Company tradesman bound for 

China and the Indies. A central goal of the Vansittart’s 

journey was to survey the Gaspar Strait, where sister 

ships of the East India Company had been lost on 

dangerous and poorly charted shoals.

The Vansittart found the shoals...by running hard 

aground, and taking on water so rapidly that the crew was 

forced to abandon ship on a tiny reef in the Java Sea. 

The waters were filled with pirates, so the crew threw 

thirteen treasure chests overboard, hoping to return 

later to reclaim them. But when they eventually made 

their way back aboard two British ships, Malay pirates 

had burned and pillaged the Vansittart and the crew 

managed to recover only three of the treasure chests.

~ based on Defi ning the Wind: The Beaufort Scale, and How a

19th-Century Admiral Turned Science Into Poetry by Scott Huler, 2004

The sinking of the Vansittart provided dramatic evidence of the value 

of an accurate nautical chart, and Francis Beaufort later became one 

of history’s premier hydrographers. Today, NOAA’s O ce of Coast Survey 

produces accurate nautical 

charts and many other 

navigational aids that help 

mariners navigate safely in 

and out of U.S. ports and 

along the U.S. coastline as 

far as 200 nautical miles 

from shore. How important 

is ocean navigation? You 

may be surprised to know 

that even in the “space 

age,” over 98% of the 

nation’s cargo is carried by 

waterborne transportation.

Here’s a chance to try your 

hand at coastal nav- igation using a modern nautical chart. Watch out for 

shoals!

What You Will Do

Discover some of the ways a nautical chart 

can help a mariner safely 

navigate in unfamiliar coastal waters

iWreck of U.S. Revenue Cutter TAHOMA which struck an 

uncharted pinnacle rock off Agattu Island, western Aleutians, 

September 20, 1914. Courtesy NOAA Ship Collection
National Oceanic and Atmospheric Administration (NOAA) 29

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What You Will Need

❒ “Segment of NOAA Nautical Chart 11445, Bahia 

Honda Key to Sugarloaf Key”

How to Do It

1. Before beginning your cruise, you need to 

know a few things about nautical charts. 

Most charts contain A LOT of information, 

including lights, buoys, wrecks, information 

about the sea bottom, shoreline features, 

water depth, and much more. These features 

are often very close together, so charts use 

many symbols and abbreviations. A complete 

list of these symbols is available in a booklet 

known as “Chart No. 1,” which can be downloaded from www.nauticalcharts.noaa.gov/mcd/

chartno1.htm (the fi le containing the entire 

publication is 85 Mb, but smaller fi les containing specifi c kinds of information are also 

available). Here are a few basics:

• The compass rose is a tool provided on all 

nautical charts to simplify the process 

of measuring directions. On the sample 

chart, the compass rose is near the upper 

center of the chart. The most commonly 

used reference point for direction on nautical charts is Earth’s geographic north 

pole (“true north”). 

• Depths on nautical charts are shown as 

many small numbers scattered over water 

areas. Depths indicated by these numbers are expressed in feet, fathoms (one 

fathom is equal to six feet), or meters. 

Contour lines (called “depth curves”) 

connect points of equal depth, typically 

6, 12, 18, 30, 60 and multiples of 60 feet. 

It’s important to remember that depths 

shown on charts are average depths, so 

the actual depth at a given location may 

be less than that shown on the chart.

• The general rule for coastal navigation is 

“red, right, returning.” This means that 

red markers, lights, or buoys should be 

on the right side of a vessel when coming 

into port. There are many exceptions to 

this general rule, though, so it is essential 

to have a chart that shows the arrangement of markers for a specifi c part of the 

coast.

• In shallow water, markers are often fl at 

“signs” fastened to wood or metal stakes. 

Red markers are usually triangular, and 

green markers are square. These markers 

are shown on a chart by red triangles and 

green squares, and usually have a number 

that also is shown on the chart.

• Buoys are shown on nautical charts by diamond-shaped symbols and a small open 

circle that indicates the location of the 

buoy. 

• Red buoys are printed in magenta and often 

have the letter “R” nearby.

• Green buoys are printed in green with the 

letter “G” nearby. 

• A number in quotation marks is the number 

painted on the buoy’s structure. 

• Lighted buoys are indicated by a magenta 

disk printed over the small circle that 

marks the buoy’s position. 

• The shape of unlighted buoys is normally 

shown by a letter. “C’ indicates a “can” 

buoy whose top has a cylindrical shape

• “N” indicates a “nun” buoy whose top is shaped 

like a cone with the pointed end cut off (this 

is called a “truncated” cone).

• Lights on nautical charts are all shown by a 

magenta symbol that looks like an exclamation point and a black dot indicating 

the light’s position. Notes alongside these 

symbols describe the color of the light 

and how it fl ashes. Some commonly used 

abbreviations are:

• Q: A light fl ashing at a rate of not less 

than 60 fl ashes per minute

• R: A red light.

• G: A green light

• If no color is indicated for a light, it is 

understood to be a white light.

• Numbers next to the symbol for a light show 

the height of the light. 
noaa.gov

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• If numbers are inside quotation marks, this 

number is painted onto the light structure. 

• Numbers followed by the letter “M” show the 

approximate range of visibility of the light 

in miles. 

For example:

 Q R 16ft “6” 9M

 indicates a red light, 16 ft high, fl ashing at a rate of not less than 60 fl ashes 

per minute (“quick fl ashing”), with the 

number “6” painted on the structure, with 

a visibility of about 9 miles

2. Now it’s time to take the Chart Challenge! 

 We will use part of NOAA Nautical Chart 

11445, which includes the Florida Keys from 

Bahia Honda Key to Sugarloaf Key. Suppose 

you are the captain of a 24-foot fi shing boat, 

and are taking some friends around the 

Keys. As the captain of a vessel, it is very 

important to know how much water is under 

your boat (underkeel clearance). This can 

vary depending on how much cargo you are 

carrying (or in this case, how many friends 

are aboard). Let’s say that your boat draws 2 

feet, which is another way of saying that the 

bottom (keel) of your boat is two feet below 

the surface. So, you’ll need to subtract two 

feet from the depths indicated on the chart 

to fi nd your underkeel clearance.

a. You and your friends board your boat at the 

dock in Doctors Arm Bay on Big Pine Key 

(to the right of the compass rose). What 

kind of markers show the location of this 

dock?

b. After casting off from the dock, you steer 

southeast into Bogie Channel. What is the 

maximum depth shown on the chart for 

the Channel?

c. As you pass through Spanish Harbor, you 

notice a low bridge ahead. The highest 

point on your boat is 10 feet above the 

water. Can you pass beneath the bridge?

d. You continue heading southeast until your 

depth sounder shows a depth of 10 feet. 

What does the chart show is probably on 

the bottom in this area?

e. Your friends are interested in snorkeling, 

so you decide to take them to the buoyed 

snorkeling area to the south of Newfound 

Harbor Keys, which is part of NOAA’s 

Florida Keys National Marine Sanctuary. 

Looking at the chart, you see that there 

are several shallow coral heads marked 

“Co” that are not marked with buoys. 

What is the water depth over these coral 

heads?

f. Since the water over the coral heads is very 

shallow, you want to steer a course that 

will avoid them. How could you use your 

depth sounder to help steer clear of these 

dangers?

g. As you travel toward the snorkeling area, 

one of your friends notices the vegetation 

on the islands to the north. According to 

the chart, what kind of vegetation is this?

h. According to the chart, the snorkeling area 

is marked by buoys labeled “A,” “B,” “C,” 

and “D.” What is the color and shape of 

these buoys?

i. After snorkeling, you decide to visit Ramrod 

Key. One of your friends says that he can 

see open water between Hopkins Island 

and Cook Island. Would this be a good way 

to go to Ramrod Key?

j. After looking at the chart, you decide to go 

to the southwest of Munson Island to enter Newfound Harbor Channel. What light 

could you use to be sure you avoid the 

shallow area to the southwest of Munson 

Island? How tall is this light?

k. After passing Munson Island, you notice 

four markers that showing the location 

of Newfound Harbor Channel. What are 

the color, shape, and numbers of these 

markers, and how would you use them to 

stay in the Channel?

SCIENCE | Service | Stewardship
National Oceanic and Atmospheric Administration (NOAA) 31

SCIENCE | Service | Stewardship Explore the Earth

l. As you enter Newfound Harbor, you notice 

three green markers and a red marker 

leading into a marina. What is the water 

depth near these markers?

m. You change your mind, and decide to visit 

Little Torch Key instead. You want to go to 

a marina that is to the east of the microwave tower on Little Torch Key. Can your 

vessel pass beneath the bridge between 

Little Torch and Big Pine Key?

n. Just before you pass beneath the bridge, 

one of your friends notices something 

sticking up out of the water. Does the 

chart show anything in this area?

o. After you pass under the bridge, you notice 

a large marina on the west side of Big 

Pine Key. Are there any obstacles between 

your vessel and this marina?

Want to Do More?

For more about nautical charts and how to use 

them, see “Plot Your Course” at oceanservice.

noaa.gov/education/lessons/plot_course.html.

To make your own nautical charts, go to: https://

oceanservice.noaa.gov/education/nautical_

charts/makechart.html St. Brendan striking out into the Atlantic - about 6th Century A.D. St. Brendan checking depths with his sounding pole. 

Courtesy NOAA.
noaa.gov

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ANN UAL IN CREASE 9'

Segment of NOAA Nautical Chart 11445, Bahia Honda Key to Sugarloaf Key
National Oceanic and Atmospheric Administration (NOAA) 33

SCIENCE | Service | Stewardship Explore the Earth

a. A red triangle numbered “2” and a green 

square numbered “1”

b. 12 feet

c. Yes, because the vertical clearance beneath the 

bridge is 11 feet

d. rocks (“rky”)

e. one to three feet

f. You could use the depth sounder to follow the 

12-foot depth contour line, which will keep 

you away from the coral heads. 

g. Mangroves

h. The buoys are yellow “cans” that have a cylindrical shape.

i. No, because the chart shows depths of less 

than one foot between these islands.

j. The flashing red light which has the number “2” 

painted on the structure, and is 16 ft tall and 

visible for about three miles.

k. There are two square green markers numbered 

“3” and “5” and two triangular red markers 

numbered “2” and “6”. You would steer your 

vessel so that the red markers are to the 

right of the vessel and the green markers are 

to the left. 

l. one to two feet

m. You can pass beneath the west end of the 

bridge because the vertical clearance is 

15 feet, but the clearance is only nine feet 

under the east end of the bridge.

n. The chart shows three poles on the south side 

of the bridge.

o. The chart shows submerged pilings to the west 

of Big Pine Key.

Don’t Peek...

Answers to the Chart Challenge

Until you have answered ALL of the Chart Challenge questions!
noaa.gov

Discover Your World With NOAA

34

What You Will Need

r Plastic coat hanger

r 6- or 12-volt DC motor (from www.sciplus.com) 

r Model boat propeller (from a hobby shop, or 

visit www.towerhobbies.com and search on 

“boat propeller”)

r Epoxy glue

r Two pieces of #28 AWG stranded wire 

(telephone wire), each about fi ve feet long

r Electrical tape

r 2 popsicle sticks

r Two fi lm canisters with lids (If you cannot fi nd 

fi lm canisters, use 2.5” to 3” screw-top plastic containers available at any craft store)

r Twelve nails, about three inches long or 1/4-

inch diameter bolts to use as weights

r One or two 6-volt batteries (two if you are 

using a 12-volt motor)

r Container of water at least 18 inches deep 

(bathtub, large laundry tub, etc)

r Hot glue gun

r Wire cutters or wire stripper or a sharp knife

r Optional: Hand drill and drill bit of same 

diameter as the motor shaft

Make a simple version 

of an underwater 

remotely operated vehicle

Some underwater robots are controlled by 

built-in computers, and can operate without 

any connection to the surface. These are called 

“Autonomous Underwater Vehicles” (AUVs). 

Many underwater robots are attached to a cable 

that allows a human operator to control the 

robot’s movements from a ship on the ocean 

surface. These robots are called “Remotely 

Operated Vehicles” (ROVs).

What can swim deep inside the 

wreck of the Titanic?

What can sit on the edge of 

an erupting underwater volcano?

What can dive thousands of feet

 below the ocean surface?

What can collect animals no one 

has seen before from 

the deep ocean?

Build an Underwater Robot Build an Underwater Robot

Underwater robots can!

Courtesy OAR/National Undersea Research Program (NURP)

Courtesy OAR/National Undersea Research Program (NURP)

What You Will Do
National Oceanic and Atmospheric Administration (NOAA) 35

SCIENCE | Service | Stewardship EXPLORE THE EARTH

Warnings

1. Do not connect a wire directly between the two 

terminals of a battery. The wire will rapidly 

become very hot and may start a fi re or cause 

serious burns!

2. Do not do this activity in saltwater because 

everything will short out and your motor will 

be ruined.

3. If you use a knife to remove insulation from 

the wires, be careful! Put the wire onto a 

cutting board and roll the knife over the wire 

to cut the insulation, but not the wire. Keep 

your fi ngers clear of the blade!

How to Do It

1. Press the propeller onto the shaft of the motor. 

If the propeller is loose on the shaft, place 

a small drop of epoxy glue on the end of the 

shaft before installing the propeller. If the 

shaft is too large for the hole in the propeller, enlarge the hole slightly with a hand drill 

fi tted with a small drill bit. (You may need 

help from an adult for this.)

2. Hold the coat hanger so that the hook is 

pointed down. Tape the motor onto the 

inside of the hook so that the propeller is 

facing up. 

3. Tape the two fi lm canisters (or screw-top 

plastic containers) with lids on, to the upper 

part of the coat hanger. 

8. Tape the other end of each wire to a popsicle 

stick or chopstick so that the bare wire end is 

hanging over the end of the stick. 

9. If you are using a 12-volt motor, connect two 

6-volt batteries in series: Strip about one 

inch of insulation off of both ends of a piece 

of #28 AWG wire about 12 inches long. Twist 

one end of the wire around the negative 

terminal of one battery, and twist the other 

end of the wire around the positive terminal 

of the other battery. 

4. Tape enough weights to the lower parts of the 

coat hanger (near the hook) so that the coat 

hanger fl oats just below the surface of the 

water. 

5. Strip about one inch of insulation off of both 

ends of each wire.

6. Twist one end of each wire onto a terminal of 

the motor. If necessary, you can keep the 

wires in place with a dab of hot glue.

7. Twist the wires together to make a single 

cable.

fi lm canisters

or screw-top 

plastic containers

motor with propeller - use 

tape to attach to hanger

wires attached to popsicle 

sticks with tape

tape weights here
noaa.gov

Discover Your World With NOAA

36

10. Test Dive Your ROV: Touch the bare end of one 

wire to one battery terminal, and the bare 

end of the other wire to the other battery 

terminal. If the propeller spins but does not 

sink, try reversing the wires on the battery 

terminals. If your ROV still doesn’t sink, you 

may need to add some more weight.

Ocean explorers use ROVs for many purposes, 

including monitoring underwater habitats, 

observing fi shes and other organisms, exploring 

deepsea environments, investigating shipwrecks, 

and studying areas too dangerous for humans 

such as active underwater volcanoes. Underwater robots are essential tools of modern ocean 

explorers. 

ROVs may be large or quite small, depending 

upon the jobs they are expected to do, but they 

all have some systems in common:

• Framework on which other components are 

mounted;

Ocean explorers use ROVs for many purposes, 

Want to Do More?

1. Add two more motors to your ROV to make it 

move horizontally. You should be able to 

make your ROV spin or move in a straight 

line, depending upon how you connect the 

motors and the battery.

2. For more underwater robots you can build, 

check out these books by Harry Bohm:

 Bohm, H. 1997. Build your own underwater robot and other wet projects. Westcoast Words. 

148 pages.

 Bohm, H. and V. Jensen. 1998. Build Your Own 

Programmable Lego Submersible: Project: Sea 

Angel AUV (Autonomous Underwater Vehicle). 

Westcoast Words. 39 pages.

• Flotation so that the ROV is neutrally buoyant 

(or nearly neutral; this means it doesn’t rise 

or sink when in the water);

• Ballast to keep the robot from rolling over;

• Power to operate motors, video cameras, and 

other equipment;

• Propulsion to move the robot up and down, 

side to side, and backward and forward;

• Control to cause the robot to perform certain 

tasks; and

• Navigation to keep track of the robot.

Some of these systems may not actually be on 

the ROV itself, but instead may be on a ship and 

connected to the ROV with a cable. Most ROVs 

carry video equipment, and many have manipulator arms that can collect samples, handle 

tools, etc.

For more information about underwater robots 

and ocean exploration, visit oceanexplorer.

noaa.gov/technology/subs/subs.html. 

Scroll down the page for links to all kinds of 

submersibles!

A Little More about Underwater Robots

Courtesy Mountains in the Sea scientifi c party: NOAA, URI/IAO and IFE

Adapted from an activity by Harry Bohm and the Marine 

Advanced Technology Education Center (MATE). 

www.marinetech.org
National Oceanic and Atmospheric Administration (NOAA) 37

SCIENCE | Service | Stewardship EXPLORE THE EARTH

Earth Origami

Carl Skalak was on a solo canoe trip in the 

Adirondack Mountains of upstate New York when a 

surprise storm brought three days of high winds and 

heavy rain that eventually turned to snow. When the 

weather cleared, the river was frozen over and he was 

surrounded by high drifts of heavy snow.

“I knew I couldn’t get out on my own, and didn’t 

know if that situation would change for the positive 

anytime soon.”

Skalak activated a Personal Locator Beacon (PLB), 

which sent a distress message to NOAA’s Search 

and Rescue Satellite Aid Tracking System (SARSAT). 

According to a SARSAT operations support officer 

for NOAA, “Mr. Skalak was facing a life-threatening 

situation because of his isolated conditions and the 

brutally frigid weather. In a matter of a few hours, he 

might have become acutely hypothermic putting his 

life at risk.” The SARSAT distress signal was relayed to the Air 

Force Rescue Coordination Center at Langley Air Force Base, 

Va., which in turn notified the nearest rescue unit, the U.S. 

Army Fort Drum Air Ambulance Detachment near Watertown, 

N.Y. A few hours after activating his PLB, Mr. Skalak was 

rescued.

~ from NOAA News 

NOAA’s National Environmental Satellite, 

Data, and Information Service (NESDIS) 

operates a search and rescue system known 

as COSPAS-SARSAT, in cooperation with 

the U.S. Coast Guard, the U.S. Air Force, 

and the National Aeronautics and Space 

Administration. This system can detect 

emergency signals from Personal Locator 

Beacons anywhere in the world. Carl Skalak’s 

PLB may have saved his life.

NESDIS uses satellites for many other 

purposes in addition to search and rescue, 

and gathers information about Earth’s 

environment that includes the location of 

major fi shing areas, hurricanes, tsunamis, 

earthquakes, fi res, and volcanoes, as well as 

information about Earth’s habitats, geology, and 

climate. NOAA makes this information available to 

many people for many di erent purposes. Here’s 

one example of a special NESDIS product: satellite 

images of Earth, assembled so that the combined 

image can be folded to produce a three-dimensional 

object that is almost round.

What You Will Do

Make a three-dimensional 

model of Earth

Earth Origami

Digital Global Image by Peter W. Slos, NOAA-NGDC
noaa.gov

Discover Your World With NOAA

38

What You Will Need

r National Centers for Environmental Information (NCEI) “Origami Balloon” image, copied 

on a color printer as large as you can make it. 

You can download a pdf file of this image (2.5 

MB) from www.ngdc.noaa.gov/mgg/image/

origamiearth.pdf

r Scissors

How to Do It

1. Cut the Origami Balloon image into a square.

2. Put the square image face-up on a flat surface 

so that the NOAA logo is right-side-up. Fold 

the bottom edge to the top edge, and make 

a crease that passes through the center of 

the square. Now unfold and refold along the 

same crease so the image is facing out. This 

will make it easier to shape the model in 

later steps. Unfold the image so it is a square 

again.

3. Bring one corner to the opposite corner and 

make a diagonal crease that passes through 

the center of the square. Unfold and refold 

along the same crease in the opposite direction. Unfold the image so it is a square again.

4. Fold the other corner to the opposite corner, 

and make another diagonal crease so that 

you now have three creases that cross in the 

center of the square. Unfold and refold along 

the same crease in the opposite direction. 

Unfold the image so it is a square again.

5. Put your thumbs on the ends of the horizontal 

crease formed in Step 2. Push the sides of 

the square together, and flatten into a triangle. The longest side of the triangle should 

be closest to you.

6. Notice that there are two pieces at each of the 

side corners of the triangle, one on top of 

the other. Take the upper piece at one of the 

side corners (a), bring it to the top of the 

triangle, and make a crease (b). Repeat with 

the upper piece of the other side corner. 

a

b

fold
National Oceanic and Atmospheric Administration (NOAA) 39

SCIENCE | Service | Stewardship EXPLORE THE EARTH

7. Turn the model over, and repeat Step 6.

8. Now there are two pieces at each of the side 

corners, one on top of the other. Fold the upper piece on one side to the center and make 

a vertical crease (a). Repeat with the upper 

piece of the other side (b). 

9. Turn the model over, and repeat Step 8.

10. Notice that there are two free points at the 

top of the model. If you turn the model over, 

there are two more free points at the top. 

Fold down the left free point at the top of the 

model (a). Open up the pocket on the left, 

and tuck the point into the pocket. Repeat 

with the right free point (b).

11. Turn the model over, and repeat Step 10.

12. Open up the shape and fi nd the open end at 

the bottom of the model.

13. Hold the model lightly by the edges, and 

blow sharply into the hole. The Earth Origami 

Balloon will infl ate!

Want to Do More?

1. See www.ngdc.noaa.gov/education/education.

html for lots of other images, maps, and 

activities.

2. Visit www.sarsat.noaa.gov/ for more information about NOAA-Satellite and Rescue 

Satellite Aided Tracking (SARSAT).

3. Visit www.noaa.gov/stories/noaa-satelliteshelped-save-307-lives-in-2016;

www.noaa.gov/stories/noaa-satelliteshelped-save-250-lives-in-2015;

www.noaa.gov/media-release/noaa-satellites-help-in-rescue-of-240-people-lastyear; and

www.noaa.gov/noaa-satellites-helped-save253-people-last-year to read more rescue 

stories.

c

d

a

b

a

b

An artist’s conception of a fully integrated environmental monitoring system including satellites, 

balloons, ships, aircraft, buoys, and data reception and 

processing facilities. Courtesy NOAA. Origami illustrations courtesy Mel Goodwin
noaa.gov

Discover Your World With NOAA

Make Your Own 

Volcano!

What You Will Need

❒ Cardboard tube from a roll of paper towels

❒ Sheets of newspaper

❒ Clear plastic tape or masking tape

❒ Corrugated cardboard, about 12 inches square

❒ Aluminum foil or homemade modeling dough 

(see recipe below)

❒ Modeling dough (store-bought or homemade)

❒ Baking soda (enough to fi ll the cardboard tube 

at least half full)

❒ Vinegar, about eight ounces

❒ Sharp knife to cut the cardboard tube

❒ Optional: spray paint; spray glue; sand; food 

coloring

Warnings 

1. Be careful with the knife! Cut on a fl at cutting 

board, and keep your fi ngers away from the 

blade!

2. Wear protective gloves and eye shields when 

handling chemicals.

2,000 feet below the ocean surface, we saw 

billowing clouds of smoke rising from the volcano’s crater. Huge clouds of yellow-tinged smoke 

and yellow balls of molten sulfur surrounded 

our underwater robot...As black chunks of 

volcanic ash began spewing out of the pit, we 

decided to retreat from the site because the 

acidic water, sulfur, and fl ying rocks were endangering our robot.

— from the Ocean Explorer 2004 Ring of Fire 

Expedition; the fi rst time any human actually saw 

an underwater volcano erupt!

What You Will Do

Make a model of a volcano, 

complete with eruption!

40
National Oceanic and Atmospheric Administration (NOAA)

SCIENCE | Service | Stewardship

How to Do It

1. Cut the cardboard tube to a length of about 

eight inches. Plug the bottom of the tube 

with a piece of modeling dough.

2. Tape the cardboard tube to the piece of corrugated cardboard with plastic tape or masking 

tape.

3. Crumple sheets of newspaper into balls, and 

tape these onto the corrugated cardboard 

around the cardboard tube. Make several different size balls so the surface tapers upward 

from the edge of the cardboard to the top of 

the cardboard tube, giving your volcano its 

shape.

EXPLORE THE EARTH ACTIVITY: MAKE YOUR OWN VOLCANO

corrugated cardboard

cardboard tube

modeling dough

baking soda

newspaper wads

modeling dough plug

spray paint

Cutaway view of the volcano model

4. Cover the balls of newspaper with a sheet of 

aluminum foil or a rolled out sheet of homemade modeling dough. Leave a hole in the 

covering for the end of the cardboard tube. 

Fold the edges of the foil under the corrugated cardboard sheet.

5. Optional: Decorate your model. Spray with 

green and brown spray paint. You may also 

want to spray on glue and dribble sand onto 

the glue before it dries.

6. Fill the cardboard tube at least half full of 

baking soda. If desired, mix several drops of 

red food coloring into the vinegar to give a 

molten lava appearance.

7. Take your model outside before erupting! Pour 

the vinegar into the tube, and stand 

back!

[Note: The volcano model made in this 

activity has the shape of a strato volcano. If you want to make a model of a 

shield volcano, cut the cardboard tube 

to a length of about three inches instead 

of eight inches (Step 1). Then follow the 

remaining instructions.]

41

Courtesy Mel Goodwin

 Recipe for 

Homemade Modeling Dough

1 cup fl our

1/2 cup salt

1 cup water

1 tablespoon cooking oil

2 teaspoon cream of tartar

(optional) food coloring

Mix all ingredients together and heat slowly, 

stirring constantly, until the mixture is thick 

and doughy. Let the mixture cool until it 

can be handled. Knead the dough ball a few 

times, then wrap in foil to store.
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42

What’s Happening

Volcanoes erupt when rocks melt 

below Earth’s surface. Liquid 

rock in the Earth’s crust is called 

magma, and tends to rise toward the 

surface. Magma collects beneath 

the surface in magma chambers, 

which often contain various gases 

as well as magma. When the magma 

and gases break through the 

Earth’s crust, an eruption happens. 

If pressure builds up inside the 

magma chamber, the eruption may 

be very violent. Very hot lava fl ows 

easily over the Earth’s surface, 

and produces fl attened volcanoes 

called shield volcanoes. If the lava 

is cooler, it is sticky and fl ows more 

slowly, producing the familiar 

cone-shaped volcanoes called 

strato volcanoes. If the eruption is 

extremely explosive and violent, 

the top of the volcano may be blown 

completely away so that only the inside of the magma chamber remains. The 

collapsed depression is called a caldera.

See the diagram above for a summary of the di erent types of submarine 

volcanoes.

This activity is adapted from “The Volcano Factory,“ a lesson from the Ocean Explorer 2004 Ring 

of Fire Expedition (oceanexplorer.noaa.gov/explorations/04fi re/background/edu/media/

RoF.volcanism.pdf); by Mel Goodwin, PhD, Marine Biologist and Science Writer, Mt. Pleasant, 

SC.

Want to Do More?

1. You can see pictures from the Ocean Explorer Ring of Fire expeditions, 

and fi nd out more about their discoveries at: 

oceanexplorer.noaa.gov/explorations/03fi re/welcome.html, 

oceanexplorer.noaa.gov/explorations/04fi re/welcome.html, 

oceanexplorer.noaa.gov/explorations/06fi re/welcome.html, and

oceanexplorer.noaa.gov/explorations/14fi re/welcome.html.

2. Some volcanoes in the United States are also part of the Ring of Fire! 

Find out more at vulcan.wr.usgs.gov/.

Most submarine volcanoes occur where tectonic plates are either moving apart or colliding. This image shows the many types of plate boundaries: 

convergent, transform, divergent, and continental rift zone. The Explorer Ridge is a divergent plate boundary at an ocean spreading ridge in the 

eastern Pacifi c, where new oceanic crust is formed. The Mariana Island Arc, on the other end of the conveyor belt in the western Pacifi c, was 

formed by the melting of the subducting Pacifi c Plate. (Image courtesy of USGS Web site. Cross section by Jose F. Vigil from This Dynamic Planet.)

42
National Oceanic and Atmospheric Administration (NOAA) 43

SCIENCE | Service | Stewardship EXPLORE THE EARTH

Now you see them, now you don’t!

Some marine animals are nearly invisible to the human eye, but become 

much easier to see if viewed through a polarizing fi lter. If you have ever 

put on a pair of polarized sunglasses to reduce glare, you have fi rst-hand 

knowledge about how a polarized fi lter can make things easier to see. 

Many animals, including fi sh, insects, birds, crabs, and shrimp have 

built-in polarized vision that helps them fi nd food, avoid predators, navigate, and communicate with mates. Scientists know very little about how 

animals see in the deep ocean, and it’s quite possible that many animals 

have been able to avoid being seen by deep ocean explorers. Maybe some 

animals can’t be seen at all with ordinary human vision, even if they are 

right in front of us! 

The Ocean Explorer Deep Scope Expeditions looked into the deep ocean 

with new eyes, including high-tech cameras that can see animals under 

extremely dim light, as well as instruments to observe animals that make 

their own light (bioluminescence) or use various types of polarization 

vision. Here are some simple experiments you can do to start exploring 

with polarized light.

What You Will Do

Experiment with polarizing

 filters, and find out whether you 

have polarization vision

A gallery of images of plankton viewed between two polarizers. In this particular setup, a normal transparent object would still be invisible. However, if the object, or animal, contains any 

birefringent (doubly refractive) substance, it will appear quite bright. Tissues such as muscle 

and tendon can be highly birefringent and are responsible for almost all the bright areas on 

these images. Photo composite: S Johnsen using images from E. Widder.

Do You Have Twisted Vision? Do You Have Twisted Vision?
noaa.gov

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44

What You Will Need

❒ Two pieces of polarizing fi lter material from 

an old pair of polarizing sunglasses, or you 

can buy polarizing fi lters from educational 

supply companies (https://www.teachersource.com; about $65 for a 15 inch x 17 inch 

sheet). The material will be marked with an 

arrow that shows the “polarization axis.” If 

you cut the fi lter into pieces, use a felt tip 

marker to draw an arrow pointing the same 

way on each of the pieces.

❒ Plastic protractor, drafting triangle, and/or 

clear plastic fork

Warning

NEVER look directly at the sun, 

even through polarized fi lters!

How to Do It

1. Shine a light through a single piece of 

polarizing fi lter material. Some of the light 

will be absorbed by the fi lter, but it probably 

won’ t matter very much how the fi lter is 

rotated. Take the fi lter outside, and look 

at blue sky, away from the sun. Now, if you 

rotate the fi lter the sky will appear darker 

and then lighter. Most light passes through 

when the fi lter is lined up with the direction 

of the polarized light.

2. Put a second piece of polarizing fi lter material 

on top of the fi rst fi lter and shine a light 

through the combined fi lter. When one of the 

fi lters is rotated, you will see that most light 

comes through when the polarization axes of 

the fi lters are pointing in the same direction 

(parallel). Less and less light passes through 

as the angle between the polarization axes 

increases, to a point at which almost no light 

is transmitted when the polarization axes are 

perpendicular to each other. 

3. Place a plastic protractor, drafting triangle, 

or clear plastic fork between two sheets of 

polarizing fi lter material and shine a light 

through the stack. When one fi lter is rotated, 

bands of color will appear and move over 

the surface of the plastic object. Flexing the 

object may reveal stress lines in the material. 

This is an example of birefringence, which is 

what happens when materials bend polarized 

light in diff erent directions. Birefringence 

occurs in many living tissues, and can make 

food organisms much more visible to marine 

animals with polarized vision.

 Note: Not all plastic objects show 

birefringence. If some of your plastic objects 

don’t work, try some others!

4. If human eyes could detect polarized light, 

you wouldn’ t need the second fi lter in these 

demonstrations. But some humans do seem 

to have very limited polarization vision. To 

fi nd out if you are one of them, try this: Face 

blue sky, away from the sun, and concentrate 

on the center of your visual fi eld (the area 

light source

polarizing fi lters parallel 

to each other

polarizing fi lters perpendicular 

to each other

The Effect of Polarizing Filters
National Oceanic and Atmospheric Administration (NOAA) 45

SCIENCE | Service | Stewardship Explore the Earth

energy particles are all vibrating in the same 

direction, the light is said to be polarized. Most 

light, including light from the sun, from ordinary 

light bulbs, and from candles is not polarized. 

Unpolarized light can be transformed into 

polarized light in several ways, including passing 

light through a filter that only transmits light 

waves that are vibrating in a single direction. 

Light waves vibrating in other directions are 

blocked. 

It may be easier to understand this kind of 

polarization by imagining a picket fence with a 

rope passing between the pickets. If we raise and 

lower one end of the rope to make a wave, it’ s 

easy to understand that the wave can only pass 

through the fence if the wave is parallel to the 

pickets, like this: 

A wave in any other direction would run into the 

pickets and be stopped. The same thing happens 

in a polarizing filter, except the molecules of the 

filter material are lined up instead of the pickets 

in the fence.

The picket fence also helps understand what happens when light is passed through two polarizing 

filters. If the rope passes through two picket fences, 

a wave in the rope will only be transmitted if the 

pickets in both fences are parallel. If one of the 

fences is rotated, the wave will be blocked, like this:

So, if we hold two polarizing filters in front of a 

light source, and then rotate one of the filters, we 

will see the light grow brighter as the molecular 

“pickets” in the two filters become parallel. Light 

can also be polarized by reflection from nonmetallic surfaces such as roads, snow, and water. 

The amount of polarization depends upon the 

type of surface and the angle at which the light 

approaches the surface. Glare from these surface 

can be reduced or eliminated by polarizing filters 

(such as sunglasses) whose molecular “pickets” 

are not parallel to the vibration direction of the 

reflected light waves. Light can also be partially 

polarized when it is scattered off of particles in 

the atmosphere.

of sky that you can see). If you see a fuzzy 

yellowish horizontal bar or bow-tie shape, 

you are seeing “Haidinger’s brush,” and 

you have a limited form of polarized vision! 

You can also try to see Haidinger’s brush 

by looking at a bright background (such 

as a well-lit white wall) through polarized 

sunglasses. 

5. Why do you suppose so many invertebrates 

have polarized vision while humans do not? 

Part of the answer is that the human eye 

consists of a single lens that focuses an 

image onto light-sensitive cells in the retina 

that transmit nerve signal to the brain. Many 

invertebrates have compound eyes made of 

hundreds (or thousands) of “simpler” eyes 

called ommatidia. Each ommatidium has a 

lens, crystalline cone, and visual cells containing rhodopsin. In vertebrates, the visual 

pigment molecules are randomly oriented, 

but in many invertebrates these molecules 

are lined up in the same direction. This makes 

it possible for these animals to detect polarized light.

What’s Happening

We can imagine light as vibrating particles of 

energy moving in a series of waves, sort of like 

the particles of water that make ocean waves. 

In some light waves, the energy particles are 

vibrating in many different directions. These 

light waves produce unpolarized light. If the 

“rope” wave passing through parallel picket fences

“rope” wave blocked when one fence is rotated
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46

Want to Do More?

One of the most famous examples of polarization 

vision is the discovery by Karl von Frisch that 

bees detect patterns of polarized light in the sky, 

and communicate directions to each other by 

dancing in a specific pattern. 

• For more information about Karl von Frisch 

and his bees, visit polarization.com/

bees/bees.html.

• For more information about Haidinger’s 

brush and polarization vision in humans, visit polarization.com/haidinger/

haidinger.html and theconversation.com/

polarised-light-and-the-super-sense-youdidnt-know-you-had-44032

• For more information about the Ocean Explorer Deep Scope Expeditions, visit:

– oceanexplorer.noaa.gov/explorations/05deepscope/welcome.html

–“Secret Communication Channels in 

the Ocean: Polarization Vision” 

oceanexplorer.noaa.gov/explorations/04deepscope/background/

polarization/polarization.html

–“Hiding in Plain Sight: Birefringence” 

oceanexplorer.noaa.gov/explorations/04deepscope/logs/aug15/

aug15.html

–“Measuring Vision in Crustaceans” 

oceanexplorer.noaa.gov/explorations/04deepscope/background/

vision/vision.html

Two images of the same leptocephalus eel larva. The top image 

is viewed under unpolarized, transmitted light. The bottom image is 

viewed under polarized, transmitted light by a camera with a polarizing filter. The increased visibility 

of the bottom image is due to the 

presence of birefringent muscle 

and connective tissue fibers. Photo 

composite: S Johnsen using images 

from E. Widder.

This Caranchid squid, about four-inches across, uses transparency 

to hide from potential predators. Open-water divers can more 

easily observe these creatures with polarizing filters. Compare the 

polarized and unpolarized images to one another. Images courtesy 

Edie Widder.

This activity is adapted from “Twisted Vision,” a lesson from the Ocean Explorer Operation Deep Scope 2005 Expedition (oceanexplorer.noaa.gov/explorations/05deepscope/background/edu/media/twisted.pdf); by Mel Goodwin, PhD, Marine Biologist and 

Science Writer, Mt. Pleasant, SC.
National Oceanic and Atmospheric Administration (NOAA) 47

SCIENCE | Service | Stewardship Explore the Earth

Be A Shipwreck Detective!

“Great acts of courage,

senseless tragedy, 

the heroism of a captain, 

the greed of a stingy shipowner, 

the stupidity of a watchman 

all find their ways into the history of shipwrecks.” 

~ from the Channel Islands National Marine Sanctuary 

Shipwreck Database Web site

Shipwrecks are an important part of our nautical heritage. Some of 

our nation’s most interesting shipwrecks are found in NOAA’s National 

Marine Sanctuary System, including the remains of the Civil War ironclad, 

U.S.S. Monitor. Some shipwrecks are hazardous to other vessels. Nautical 

charts produced by NOAA’s Office of Coast Survey show the location of 

known shipwrecks and other hazards to navigation.

In September 2003, NOAA’s Office of Ocean Exploration and Research 

visited a newly discovered shipwreck in the Stellwagen Bank National 

Marine Sanctuary on the coast of Massachusetts. Underwater 

archaeologists studied the wreck to learn more about what happened to 

cause the ship to sink. Now it’s your turn to be a Wreck Detective! Storm, shipwreck, and sea monster. Archival Photograph by Mr. Sean Linehan, NOS, NGS

Examine information about items found in and around the 

Stellwagen Bank shipwreck, and draw conclusions about the p 

ship, who was aboard, and why the ship sank

What You Will Do
noaa.gov

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48

How to Do It

1. Your fi rst task is to organize information about 

where the artifacts were found on the shipwreck. The “List of Artifacts” gives a grid location for each item and how deeply artifacts 

were buried (so “22 inches from surface” 

means the object was buried 22 inches into 

the sea bottom). Archaeologists often use 

a grid system to precisely record the exact 

location of artifacts and their relationship 

to each other. You have already used grids 

to express location if you have ever played 

Battleship, or even Bingo. 

What You Will Need

❒ “Grid Reference System for Unidentifi ed 

Shipwreck Q11WRK5” and “List of Artifacts 

Retrieved from Unidentifi ed Shipwreck 

Q11WRK5”

❒ Imagination

2. As you look at the description of each artifact, 

think about how deep the artifact was 

below the surface, and what other artifacts 

were found nearby. Then consider what the 

artifacts may suggest about

• the specifi c identity of the ship that sank;

• age of the vessel;

• the vessel’s purpose;

• who was aboard; and

• why the vessel sank.

3. Write your conclusions on a piece of paper. 

Then read “The Story of the Steamship 

Portland” on Page 50.

Want to Do More?

1. Visit oceanexplorer.noaa.gov/explorations/03portland/welcome.html the Web 

site for the Steamship Portland expedition.

2. For another shipwreck activity see “Lost at 

Sea: Sunken Slave Ship” activity from Newton’s Apple episode 1502. You can access 

this activity from www.reachoutmichigan.

org/funexperiments/agesubject/lessons/

newton/sunken.html.

3. Visit stellwagen.noaa.gov/maritime/portland.html for more information on the 

wreck of the Steamship Portland.

4. Visit thunderbay.noaa.gov/shipwrecks/welcome.html for information on Thunder Bay 

National Marine Sanctuary.

5. Visit monitor.noaa.gov for information on 

the Monitor National Marine Sanctuary.

This activity is adapted from “Wreck Detectives,“ a lesson 

from the Ocean Explorer Steamship Portland Expedition 

(oceanexplorer.noaa.gov/explorations/03portland/

background/edu/media/portlandwreckdetec.pdf); by Mel 

Goodwin, PhD, Marine Biologist and Science Writer, Mount 

Pleasant SC.
National Oceanic and Atmospheric Administration (NOAA) 49

SCIENCE | Service | Stewardship Explore the Earth

Grid Reference Description

E19–E23 

& F19-F23 Heavy metal structure, diamond shaped, 

 partially buried

D10 Gentleman’s gold ring, 22 inches from surface

E14 Heavy mahogany chair, velvet upholstery, 

 40 inches from surface

D10 China plate, 100 inches from surface

G10 China chamber pot, 20 inches from surface

D13 Silver flatware, engraved letter “P,” 

 100 inches from surface

F14 China cup, 100 inches from surface

D10 Brandy flask, 20 inches from surface

F14 Domed skylight, 16 inches from surface

D13 Carved mahogany headboard, 

 28 inches from surface

F13 Ebony piano keyboard, 

 22 inches from surface

C19-C24 Massive paddlewheel, partially buried

G10 Child’s rocking chair, mahogany, 

 24 inches from surface

D13 Lady’s dress shoe, 26 inches from surface

G10 Shaving straight razor, 22 inches from surface

H17 Silver buckle, 28 inches from surface

Grid Reference Description

D13 China chamber pot, 24 inches from surface

E11 Carving knife, 92 inches from surface

D10 Man’s leather dress shoe, 

 24 inches from surface

B13 Carved wooden plank, 

 letters “RTLAND;” left side broken

E11 Silver serving platter, 92 inches from surface

E5 Rusted iron mass, possibly chain

F21 Heavily rusted iron mass, possibly tools, 

 100 inches from surface

E11 Ship’s wheel, 12 inches from surface

D10 Small mahogany chest of drawers, 

 28 inches from surface

E33 Rudder, partially buried

G19-G24 Massive paddlewheel, partially buried

E17 & F17 Smokestacks

NOTE: Extensive debris around main wreck, mostly 

large timbers and pieces of heavy equipment; 

several lifeboat remnants outside main wreck. 

Less obvious structural debris in quadrats 

numbered 25 and higher; these quadrats contain 

mostly silt down to the apparent hull of the vessel 

at approximately 140 inches.

List of Artifacts Retrieved from Unidentified Shipwreck Q11WRK5
noaa.gov

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50

On Thanksgiving Saturday, November 26, 1898, the passenger steamship Portland left Boston 

Harbor with more than 190 passengers and crew 

bound for Portland, Maine. The Portland was a 

state-of-the-art, luxury ship with velvet carpets, 

mahogany furniture, and airy staterooms. By 

1898, paddlewheel steamboats had revolutionized 

transportation in the United States. Faster and more 

reliable than sailing ships, paddlewheelers could 

also maneuver in waters that were too shallow for 

sailing ships. By the 1870’s, many people routinely 

boarded steamboats to travel between port cities. But 

the paddle-wheelers had a serious flaw: they were 

built long and narrow (the Portland was 281 feet long 

and 62 feet wide), and this shape combined with 

a shallow draft (the Portland’s keel was only 11 feet 

below the water line) made these ships extremely 

unstable in high seas. 

When the Portland steamed out of Boston Harbor, 

she ran straight into a monster storm moving up the 

Atlantic coast with northeasterly winds gusting to 

90 mph, dense snow, and temperatures well below 

freezing. Facing a roaring northeasterly wind, the 

captain could not turn back; to have done so would 

have placed the ship broadside to wind and waves that 

would surely have capsized her. The only choice was 

to continue to head northeast into the waves, and hope 

to ride out the storm. Four hours after her departure, 

a vessel believed to have been the Portland was seen 

near Thatcher Island, about 30 miles northeast of 

Boston. But the Portland was apparently unable to 

make much more progress against the storm.

At 5:45 a.m. on the morning of November 27, four 

short blasts on a ship’s steam whistle told the keeper 

of the Race Point Life-Saving Station on Cape Cod 

that a vessel was in trouble. Seventeen hours later, 

life jackets, debris, and human bodies washed ashore 

near the the Race Point station, confirming that the 

Portland and everyone aboard had been lost in one of 

New England’s worst maritime disasters. The loss of 

the Portland underscored the inherent instability of 

sidewheel paddleboats. Sidewheelers were gradually 

replaced by propeller-driven boats, which have a 

lower center of gravity.

For 90 years, the location of the Portland wreck was 

unknown, despite intense and continuing public 

interest. In April 1989, members of the Historical 

Maritime Group of New England found wreckage 

in water more than 300 feet deep that they were 

certain had been the Portland. Because of the depth, 

however, the discoverers were unable to obtain 

photographs or other evidence that could confirm 

their find. Thirteen years later, on August 29, 

2002, the U.S. Commerce Department’s National 

Oceanic and Atmospheric Administration (NOAA) 

confirmed that the wreck of the Portland had been 

found within NOAA’s Stellwagen Bank National 

Marine Sanctuary. Using side-scan sonar and a 

remotely operated vehicle (ROV), scientists obtained 

high-quality video and side-scan images in a joint 

research mission of the Stellwagen Bank National 

Marine Sanctuary and the National Undersea 

Research Center at the University of Connecticut.

Massive storms during late October and November 

are not particularly unusual in the New England 

states. At this time of the year, large cold air masses 

from Canada cross the midwestern states on a 

regular basis. At the same time, the Atlantic Ocean 

retains its summer heat and these warm waters 

sometimes spawn hurricanes. When the eastmoving cold air masses encounter the warm, humid 

oceanic air, the result is what New Englanders call 

“Nor’easters:” storms that are often severe, and are 

often the cause of maritime disasters. L

The Story of the Steamship Portland Clues from the 

“List of Artifacts Retrieved from 

Unidentified Shipwreck Q11WRK5:”

The large paddlewheels near the middle of the ship 

clearly suggest a sidewheel paddleboat. This was 

a large vessel for a paddlewheeler; over 280 feet. 

The diamond shaped metal structure is probably 

the remains of a walking beam engine, a common 

design in ships of this type. The fact that this was 

a large paddlewheeler narrows its probable vintage 

to between 1890 and 1910. Artifacts in quadrats 

D10, D13, and G10 suggest that men, women, and 

children may have been aboard, and these areas 

may have been staterooms. The fact that artifacts 

in these areas were close to the surface suggests 

that these staterooms were on or near the deck of 

the vessel. Eating utensils recovered from more 

than 80 inches below the surface suggest a dining 

area, located on a lower deck. Engraved silver 

flatware and the carved wooden plank are valuable 

clues, suggesting that the name of the vessel may 

have begun with the letter “P” and ended with 

the letters “rtland.” Many of the artifacts suggest 

wealth and luxury. This vessel almost certainly 

carried some wealthy passengers.

Think about the size of the debris field. Ships that 

sink suddenly (such as those sunk in battle) often 

have a rather small debris field. Ships that sink 

with lots of movement, on the other hand (such 

as ships sunk in storms) are likely to have larger 

debris fields. This ship has an extensive debris field, 

suggesting that a lot of motion, possibly due to a 

storm, was involved in her sinking.
National Oceanic and Atmospheric Administration (NOAA) 51

SCIENCE | Service | Stewardship Explore the Earth

“OK, we’re 8,000 feet deep now...

Hey, there’s something on the bottom that 

looks like twisted stone chimneys with some 

kind of hot fluid jetting out from the top...

Wait a minute...there’s all kinds of animals 

down here; giant clams and huge red worms 

sticking out of eight-foot-long tubes...

Believe me, no one has ever seen anything like 

this before...“

These observations, made on February 17, 1977 

aboard the deep-diving submarine Alvin, were 

one of the biggest scientific discoveries of the 

last century: a totally new ecosystem thriving at 

near-freezing temperatures in the total darkness of the deep Pacific Ocean, and under water 

pressure more than 275 times greater than the 

pressure at sea level. 

These ecosystems, now called “hydrothermal 

vent communities,” do not depend upon green 

plants and sunlight for their food. Instead, 

they are able to use chemicals in the hot fluids 

pouring out of the twisted stone “chimneys.” 

Photograph of three small (12 inches tall) actively venting spires 

sitting on top of one of the chimneys in the Black Forest vent field. 

The chimneys themselves are about 23 feet tall. The fluids here 

are venting at 240oC (464°F) and are expelling black (mineral-rich) 

smoke into the ocean.

What You Will Do

Make a three-dimensional 

model of a giant tubeworm

Weird, Red, and Slightly Gross!

This process is called “chemosynthesis.” Most 

hydrothermal vent animals aren’t able to use 

these chemicals all by themselves. Instead they 

have partnerships with other organisms, usually 

bacteria. The tubeworms, for example, have a 

large organ called a trophosome, that contains 

chemosynthetic bacteria. They do not have a 

mouth, stomach, or intestines. The worms have 

long tentacles that stick out from the end of the 

tube. Inside the tentacles, the worms’ blood 

contains hemoglobin (like human blood) that 

can absorb chemicals from the surrounding 

water. The blood carries these chemicals to 

bacteria living in the trophosome. The bacteria 

produce food that provides nutrition to the 

tubeworm. 

In 2002, 2006, and 2011, NOAA supported 

expeditions to the Galapagos to revisit the site 

where hydrothermal vents were first seen. See the 

links below for more on these expeditions:

oceanexplorer.noaa.gov/okeanos/explorations/

ex1103/logs/photolog/photolog.html

oceanexplorer.noaa.gov/explorations/05galapagos/logs/photolog/photolog.html

oceanexplorer.noaa.gov/explorations/02galapagos/logs/photolog/photolog.html
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52

What You Will Need

1. Materials that can represent parts of the 

tubeworm (see the drawing below). Here are 

some ideas, but with a little imagination you 

can probably fi nd lots of other things to use:

• Cardboard tubes (mailing tubes or paper 

towel rolls) for the trunk and tube

• Pipe cleaners for tentacles

• Modeling clay or papier mâché (newspaper and glue made from fl our and 

water) for the vestimentum

• Sponge for the trophosome

• Small corks or pieces of round cereal can 

represent bacteria

2. Other supplies: glue, scissors, poster board, 

colored markers, and/or spray paint

3. Optional: a rotten egg in a tightly-closed jar

How to Do It

Since most of a tubeworm is hidden inside the 

tube, you should build your model as a “cutaway” (also called a cross section) so that the 

major structures can be seen. Here are the 

parts of a tubeworm that should be included in 

your model:

• Tentacles – All the tentacles together 

are called the “plume”; these should 

be colored red, since they contain 

hemoglobin.

• Vestimentum – This is a muscular structure 

that has several functions:

– It helps to hold the worm in its tube;

– It generates new tube material;

– It contains pores that release sperm or 

eggs during spawning; 

– It contains the tubeworm’s version of a 

heart and a brain.

• Trophosome – This dark green-brown organ has 

a spongy texture, and contains bacteria that 

use oxygen, carbon dioxide, and hydrogen 

Tubeworm

sulfi de to make food for themselves as well 

as the worm; be sure to include something 

that represents bacteria (there are billions 

of bacteria in the trophosome, but you don’t 

need to include all of them in your model!)

 A very noticeable feature about tubeworms 

is their smell. One of the chemicals used by 

chemosynthetic bacteria is hydrogen sulfi de, 

which is what makes rotten eggs smell the way 

they do. If you want to include this feature in 

your model, you should probably put a rotten 

egg (or other source of hydrogen sulfi de) in 

a glass jar with a tight-fi tting lid so you can 

control the smell.

Plume

Blood Vessel

Vestimemtum

Heart

Trophosome

Tube

Body Cavity (inside 

the Trunk)

Opisthosome

• Trunk – This is where waste is 

stored, since tubeworms have 

no mouth, stomach, intestines, 

or anus (nasty, maybe, but it 

works for the tubeworm!)

• Tube – This is a hard hollow 

cylinder, and provides 

protection for the worm like 

the shells of other animals. 

The tentacles can be pulled 

completely inside the worm to 

avoid predators. 

• Opisthosome – This organ (like 

the vestimentum) produces new 

tube material and helps anchor 

the worm in its tube. 
National Oceanic and Atmospheric Administration (NOAA) 53

SCIENCE | Service | Stewardship Explore the Earth

Want to Do More?

1. Visit www.whoi.edu/oceanus/viewArticle.

do?id=2400 to find out about black smokers 

(the “chimneys” around hydrothermal vents 

that emit hot fluids). 

2. Visit oceanexplorer.noaa.gov/edu/themes/

vents-and-volcanoes/welcome.html for more 

information and activities on hydrothermal 

vent communities.

3. Visit www.divediscover.whoi.edu/vents/index.

html to learn more about the discovery of 

hydrothermal vents, including recordings of 

scientists aboard the submarine Alvin.

4. Visit oceanexplorer.noaa.gov/

explorations/02fire/logs/magicmountain/

welcome.html for fly-through movies of the 

Magic Mountain hydrothermal vent site on 

Explorer Ridge (in the northeastern Pacific 

Ocean, about 150 miles west of Vancouver 

Island, British Columbia, Canada).

This activity is adapted from “Let’s Make a Tubeworm!”, 

a lesson from the Ocean Explorer 2002 Gulf of Mexico 

Expedition: oceanexplorer.noaa.gov/explorations/02mexico/

background/edu/media/gom_tube_gr56.pdf); by Mel 

Goodwin, PhD, Marine Biologist and Science Writer, Mt. 

Pleasant, SC.

Riftia tubeworms, mussels, and scavenging crabs found at the 

hydrothermal vent site East Wall, located at 90 North on the East 

Pacific Rise. Photo courtesy of C. Van Dover, NOAA.

Giant tubeworm, RIftia pachyptila, from the 

hydrothermal vents at the East Pacific Rise 

at 2500m depth. Each individual in the photo 

exceeds one meter in length. Courtesy Monika 

Bright, University of Vienna, Austria. NOAA

WOW!!!!

These tube worms 

are about 

3 feet long!
noaa.gov

Discover Your World With NOAA

54

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA
National Oceanic and Atmospheric Administration (NOAA) 55

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

NOAA programs to understand 

Earth’s Weather, Oceans, 

and Climate help make our homes and 

communities safer, and are important for 

reliable commerce and transportation. Water 

transportation is the backbone of the U.S. 

economy. Almost everyone travels in aircraft 

and motor vehicles. But airplanes, ships, 

trucks, and automobiles are all a ected by 

bad weather. Delays due to bad weather cost 

U.S. airlines more than $4 billion every year. 

Bad weather is also involved with over 1.5 

million motor vehicle accidents each year; 

and these accidents caused about 800,000 

injuries and 7,000 deaths. NOAA contributes 

to safe travel and transportation in many 

ways, including up-to-the-minute weather 

information and warnings from the National 

Weather Service, nautical and navigational 

charts, satellites that gather data on weather 

and ocean conditions around the world, and 

creating accurate maps of Earth’s surface.

Besides understanding Earth’s weather, 

NOAA also works to understand climate. 

Earth’s climate has changed many times, and 

those changes can have a big impact on life 

in America. When some of the fi rst people 

arrived in North America between 15,000 

and 30,000 years ago, two great ice sheets 

covered much of the continent. About 1,000 

years ago, a prolonged drought forced the 

Anasazi people of the southwestern United States to abandon large settlements in 

Colorado, Utah, Arizona, and New Mexico. A 

shorter drought caused to the “dust bowl” 

in the midwestern U.S. during the 1930’s. 

NOAA’s climate programs focus on detecting 

signs of climate change, and on helping individuals and communities decide how to cope 

with the e ects of changing climate.

Have fun Understanding the Earth with 

these activities from NOAA programs:

Satellite Communications

• Follow That Hurricane!

• Build Your Own Weather Station

• Be a Citizen Weather Reporter

• Tornado in a Bottle

• Tree Ring Detective

• Your Own El Niño

• Wooly Magma

 and more!

UNDERSTAND the Earth

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA

Courtesy NOAA
noaa.gov

Discover Your World With NOAA

56

Follow That Hurricane!

Startled man ready to run after a hurricane driven wave smashes into seawall

Historic NWS Collection. Courtesy NOAA.

Follow That Hurricane!

“Devastating damage expected... A most 

powerful hurricane with unprecedented 

strength... Most of the area will be uninhabitable for weeks, perhaps longer... At least 

one half of well constructed homes will have 

roof and wall failure... all wood framed low rising apartment buildings 

will be destroyed... High rise o ce and apartment buildings will sway 

dangerously, a few to the point of total collapse... airborne debris will be 

widespread... persons, pets, and livestock exposed to the winds will face 

certain death if struck...” 

~ from Urgent Weather Statement issued by Robert Ricks, Meteorologist, National Weather Service, New Orleans/Baton Rouge O ce, August 28, 2005

This weather statement, warning of Hurricane Katrina’s approach, 

probably saved many lives. Providing weather forecasts and warnings is 

one of the ways the National Weather Service carries out its mission to 

protect life and property and enhance the national economy. The National Hurricane Center (part of the National Weather Service) tracks tropical 

storms and hurricanes, and issues hurricane watches and warnings when 

the storms get close to the U.S. Here’s how you can track the approach of 

tropical storms and hurricanes.

What You Will Do

Track a hurricane on the same 

type of chart used at the 

National Hurricane Center
National Oceanic and Atmospheric Administration (NOAA) 57

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

What You Will Need

❒ Copy of the “Western Atlantic Hurricane Tracking Chart.” To download one yourself, go to 

www.nhc.noaa.gov/tracking_charts.shtml, 

scroll down the page to the blank tracking 

charts and click on the Western Atlantic one.

❒ Pencil and eraser

❒ A record of hurricane locations from the 

National Hurricane Center, or from historical 

hurricane records; records from four famous 

hurricanes are found on the following pages.

How to Do It

1. The location of a hurricane on a particular 

date and time is described by the latitude 

and longitude of the storm’s center, called 

the “eye.” Latitude measures how far north 

or south a location is from the equator, and 

longitude measures how far east or west a location is from a line that goes from the North 

Pole to the South Pole, passing through 

Greenwich, England. On the “Atlantic Basin 

Hurricane Tracking Chart,” latitude is shown 

by horizontal lines and longitude is shown 

by vertical lines. Latitude and longitude are 

measured in degrees. Hurricane coordinates 

are given in pairs, with latitude written 

before longitude. So, the location of Bermuda would be written as: 32.3°N, 64.7°W. The 

“N” means that the location is north of the 

equator, and the “W” means that the location 

is west of Greenwich, England.

2. To plot the location of a storm:

(a) Find the latitude of the storm (the fi rst 

coordinate in the pair), and locate the 

horizontal line on the map that matches 

this latitude.

(b) Find the longitude (the second coordinate 

in the pair, usually followed by a W or E), 

and locate the vertical line on the map 

that matches this longitude.

(c) Find the place on the map where the two 

lines intersect. This is the location of the 

storm eye. Draw the symbol for a hurricane or a tropical storm (depending upon 

the kind of storm you are tracking) at this 

spot, and write the date and time next to 

the symbol. (See above right).

3. Try plotting the track of one or more famous 

hurricanes. You are now ready to plot real 

storms during the next hurricane season! 

You can get coordinates from NOAA WeatherRadio-All Hazards, newspapers, or from 

http://www.nhc.noaa.gov.

Is It a Tropical Depression, 

Tropical Storm, or Hurricane?

Tropical Depressions, Tropical Storms, and Hurricanes are all cyclones, which are areas of low 

pressure in the atmosphere that have a spiralling 

inward pattern of air movement. In the Northern 

Hemisphere, the spiral turns counterclockwise, 

while cyclones in the Southern Hemisphere have 

spirals that turn clockwise.

A Tropical Depression is a tropical cyclone in 

which the maximum sustained wind speed is 38 

mph or less.

A Tropical Storm is a tropical cyclone in which the 

maximum sustained wind speed ranges from 39 

mph to 73 mph.

Hurricanes are tropical cyclones with maximum 

sustained wind speeds of 74 mph or greater. Hurricanes are classifi ed into fi ve categories:

• Category One: Winds 74-95 miles per hour 

• Category Two: Winds 96-110 miles per hour 

• Category Three: Winds 111-130 miles per hour 

• Category Four: Winds 131-155 miles per hour 

• Category Five: Winds greater than 155 miles 

per hour Hurricane Katrina Satelite View. Courtesy NOAA

Hurricane Symbol:

Tropical Storm Symbol:
noaa.gov

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58

Is Your Family Disaster-Ready?

Visit https://www.ready.gov/kids/build-a-kit for information about how to 

make a Disaster Supply Kit.

Want to Do More?

Check out these Web sites:

• http://www.nhc.noaa.gov/HAW2/english/intro.shtml – Hurricane 

Awareness from the National Hurricane Center

• www.nhc.noaa.gov/aboutnames.shtml – The list of World-Wide Tropical 

Cyclone Names

 • www.nhc.noaa.gov/aboutsshs.shtml – Information about the Saffir-Simpson Hurricane Scale

• http://www.nws.noaa.gov/om/hurricane/resources/

TropicalCyclones11.pdf – “Tropical Cyclones,” a very comprehensive 

guide to hurricanes and how to prepare for them

• http://www.nhc.noaa.gov/pastall.shtml – Historical Hurricane Tracks 

Web site, with information about dozens of hurricanes in the Atlantic 

and East-Central Pacific Ocean Basins. Scroll down to Past Track 

Seasonal Maps to select information about dozens of hurricanes in 

the Atlantic and East-Central Pacific Ocean Basins.

Track Coordinates of Some Famous Storms

Hurricane Hugo

Location and Windspeed at 0000 GMT

Date Latitude Longitude Wind Speed

 (North) (West) (knots)

9/11/1989 13.2 23.7 30

9/12/1989 12.5 31.0 40

9/13/1989 12.6 38.2 55

9/14/1989 12.9 44.9 70

9/15/1989 13.8 50.5 100

9/16/1989 14.8 56.1 135

9/17/1989 16.1 60.4 120

9/18/1989 17.2 64.1 130

9/19/1989 19.7 66.8 100

9/20/1989 23.5 69.3 90

9/21/1989 27.2 73.4 100

9/22/1989 31.7 78.8 120

9/23/1989 42.2 80.2 35

9/24/1989 52.0 62.0 40

9/25/1989 54.0 57.0 40

Courtesy FEMA

Courtesy NOAA
National Oceanic and Atmospheric Administration (NOAA) 59

Science | Science | SERVICE SERVICE | Stewardship | Stewardship UNDERSTAND THE EARTH

Hurricane Andrew

Location and Windspeed at 0000 GMT

Date Latitude Longitude Wind Speed

 (North) (West) (knots)

17/8/1992 11.2 37.4 30

18/8/1992 13.6 46.2 40

19/8/1992 16.3 53.5 45

20/8/1992 19.8 59.3 40

21/8/1992 23.2 62.4 45

22/8/1992 25.3 65.9 55

23/8/1992 25.6 71.1 110

24/8/1992 25.4 77.5 125

25/8/1992 26.2 85.0 115

26/8/1992 28.5 90.5 125

27/8/1992 31.5 91.1 35

28/8/1992 34.4 86.7 20

Hurricane Floyd

Location and Windspeed at 0000 GMT

Date Latitude Longitude Wind Speed

 (North) (West) (knots)

8/9/1999 15.0 46.9 30

9/9/1999 16.7 52.6 45

10/9/1999 18.3 57.2 60

11/9/1999 20.8 60.4 80

12/9/1999 22.7 64.1 85

13/9/1999 23.4 68.7 125

14/9/1999 24.5 74.0 115

15/9/1999 27.1 77.7 115

16/9/1999 32.1 78.7 90

17/9/1999 40.6 73.5 50

18/9/1999 44.8 67.3 40

19/9/1999 48.0 56.3 35

Hurricane Katrina

Location and Windspeed at 0000 GMT

Date Latitude Longitude Wind Speed

 (North) (West) (knots)

24/8/2005 23.4 75.7 30

25/8/2005 26.0 77.7 45

26/8/2005 25.9 80.3 70

27/8/2005 24.6 83.3 90

28/8/2005 24.8 85.9 100

29/8/2005 27.2 89.2 140

30/8/2005 32.6 89.1 50

31/8/2005 38.6 85.3 30

Three views of Hurricane Andrew on 23, 24, and 25 August 1992 as the hurricane moves East 

to West. Time lapse satellite image courtesy NASA.
noaa.gov

Discover Your World With NOAA

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National Oceanic and Atmospheric Administration (NOAA) 61

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

Build Your Own Weather Station Build Your Own Weather Station

“I believe there is a train under here somewhere!”

Standing tall on North Dakota snow. A March blizzard nearly buried utility poles. 

Caption jokingly read “I believe there is a train under here somewhere!” 

Courtesy Dr. Herbert Kroehl, NGDC

Every year, thousands of lives and millions of dollars are saved by severe 

weather warnings from the National Weather Service. From its earliest 

beginnings (on February 9th, 1870), the primary mission of the National 

Weather Service has been to protect life and property by providing information about dangerous weather conditions. Originally, the National Weather 

Service was called “The Division of Telegrams and Reports for the Benefi t of 

Commerce” and was part of the U.S. Army. Later, its name was shortened to 

the Weather Bureau and it became part of the Department of Agriculture, 

then the Department of Commerce. 

The fi rst “weathermen” were “observing-sergeants” of the Army’s Signal 

Service Corps. Weather forecasting in those early years was based almost 

entirely on the assumption that the weather observed in one location on 

a particular day would move to downwind locations on following days. 

Today, satellites, computers, and a variety of scientifi c instruments are 

added to this basic assumption to make accurate weather predictions 

and provide warnings about dangerous weather. 

Here’s how you can make your own weather observation station!

“I believe there is a train under here somewhere!”

What You Will Do Build six instruments that you can use to make 

scientific measurements of your local weather
noaa.gov

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62

What You Will Need

r Five paper cups - Three ounce size

r Two straight plastic soda straws

r Straight pin

r Paper punch

r Stapler

r Sharp pencil with eraser

r Felt tip marker

r Watch or timer

Warning

Be careful with the straight pin!

How to Do It:

1. Using a paper punch, punch a hole in four 

paper cups about 1/2-inch below the rim of 

the cups.

2. Punch four equally spaced holes in a fi fth 

paper cup about 1/4-inch below the rim, and 

a fi fth hole in the center of the bottom of the 

cup (you will probably need to use the pencil 

to make the hole in the bottom).

3. Push a soda straw through the hole in one 

of the fi rst four cups. Flatten the end of the 

straw and staple it to the side of the cup 

opposite the hole. Repeat this step with the 

other straw and another of the fi rst four 

cups.

4. Slide one of the cup and straw assemblies 

through two opposite holes in the side of the 

fi fth cup. Push another one-hole cup onto 

the straw, and turn this cup so that the open 

ends of the two cups on the straw face in 

opposite directions. Flatten the end of the 

straw, and staple it to the side of the second cup. Measure the distance between the 

centers of the two cups. This is the diameter 

of your anemometer.

Build an Anemometer to Measure Wind Speed

3 oz. paper cup

Straw

Pencil

Straight pin
National Oceanic and Atmospheric Administration (NOAA) 63

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

5. Repeat Step 4 with the remaining cup and 

straw assembly and the remaining one-hole 

cup. Before stapling the end of the straw to 

the last cup, turn the cups so that the open 

end of each cup faces the closed end of the 

next cup.

6. Adjust the cup and straw assemblies so that 

they are centered inside the fi fth cup. Push 

the straight pin through the two straws 

where they intersect.

7. Push the eraser end of the pencil through the 

hole in the bottom of the fi fth cup, and push 

the straight pin into the eraser as far as it 

will go. Your anemometer is ready to use!

8. To use the anemometer, hold the pencil 

vertically in a wind, and count the number 

of revolutions per minute (use the felt tip 

marker to make a mark on one cup so that 

you can easily see when the cup has travelled through one complete revolution). To 

convert revolutions per minute (rpm) into 

approximate wind speed:

a. Multiply rpm by the diameter (in inches) of 

your anemometer (measured in Step 4) 

b. Multiply the result by 0.003. This is the 

approximate wind speed in miles per hour. 

 This calculation does not give exact wind 

speed, because drag, friction, and other 

forces also aff ect the speed at which your 

anemometer rotates. 

Finished Anemometer

Anemometer 
noaa.gov

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64

Build a Weather Vane to Find Wind Direction

What You Will Need

r Broomstick or long wooden dowel, about one 

inch diameter

r Aluminum baking dish, about six inches x nine 

inches

r Wood stick, about 3/4 inch square and 12 

inches long

r Nail, about one inch long

r Metal washer with a hole slightly larger than 

the nail

r Duct tape

r Small saw or serrated knife

r Scissors strong enough to cut the aluminum 

baking dish

r Ruler or tape measure

r Silicone or other glue that will stick to aluminum

r Leather gloves

r (Optional) Hand drill, and small drill bit 

slightly larger than the nail

Warning

Be careful of the sharp edges on the pieces of cut 

aluminum! Use gloves to protect your hands until 

the edges are taped.

Mark this spot on the upper surface of the 

stick, and drive a nail through the marked 

spot. Be careful: if the nail is too big, the 

stick will probably split. To avoid this, drill a 

hole slightly larger than the nail through the 

marked spot. You may need an adult to help 

with the drilling.

3. Cut the head and tail pieces of the Weather 

Vane from the aluminum baking dish using 

the pattern as a guide. Be Careful—The 

Edges Are Sharp! Use duct tape to cover the 

sharp edges.

How to Do It

1. Use the saw or serrated knife to cut a notch 

about 1/2-inch deep into each end of the 

wood stick. The notches should be parallel 

(see drawing on page 65).

2. Rotate the stick so that the two slots are vertical. Use the ruler or tape measure to find the 

exact center of the wood stick. 

tail

head
National Oceanic and Atmospheric Administration (NOAA) 65

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

4. Fit the head piece into one of the slots in 

the wood stick and fi t the tail piece into the 

other slot. Glue the head and tail pieces into 

place and allow the glue to dry.

5. Attach the Weather Vane to the broomstick or 

dowel, by placing the washer on one end of 

the dowel and hammering the nail through 

the wooden stick into the dowel. 

 Be sure the stick still moves freely around the 

nail. 

6. Mount your Weather Vane outside where there 

are no nearby obstructions to block the wind. 

Try to get the dowel as high as you can while 

still keeping it steady and secure. 

 Winds are named according to the direction 

from which the wind is blowing, so a “north 

wind” is blowing from the north. The head of 

the Weather Vane will point to the direction 

from which the wind is blowing. 

head

tail

nail

dowel

washer

broom or long 

wooden dowel

Finished Weather Vane
noaa.gov

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66

Build a Barometer for Measuring Atmospheric Pressure

What You Will Need

r 12-inch ruler

r Drinking glass or other container with sides 

tall enough to support the ruler

r Clear plastic drinking straw or piece of clear 

plastic tubing, about 12-inches long 

r Modeling clay or chewing gum

r Clear tape

r (Optional) Food coloring

How to Do It

1. Tape the plastic straw or plastic tubing to the 

ruler so that one end is lined up with the 

“1/2-inch” mark on the ruler.

2. Stand the ruler-tubing assembly upright in 

the glass (or other container), and tape the 

assembly to the top of the container.

3. Fill the container about 3/4-full of water. If 

you want colored water, fi rst mix food coloring with the water in another container.

4. Use the modeling clay or chewing gum (you’ll 

have to chew it until it is soft enough) to plug 

the end of the straw or plastic tubing near 

the top of the ruler.

5. Carefully pour out some of the water so the 

container is about half full. Be sure the lower 

end of the straw or tubing stays beneath the 

water surface while you do this! When you 

are fi nished, the water in the straw or tube 

should be higher than 

the water in the container. Your barometer 

is now fi nished. Since 

barometers are sensitive to minor changes 

in weather conditions, 

keep your barometer 

indoors for greatest 

accuracy.

6. Keep a daily record of 

the height of the water 

in the tube, using the 

scale on the ruler. 

The water level in the 

tube will rise and fall 

as atmospheric pressure changes. When 

atmospheric pressure 

increases, air presses on 

the surface of the water 

in the container causing 

the height of the water 

in the tube to rise. When atmospheric pressure decreases, there is less pressure on the 

surface of the water in the container so the 

height of the water in the tube falls. Decreasing atmospheric pressure usually indicates 

that a low pressure area is approaching, and 

this often brings clouds and rain. Increasing 

atmospheric pressure often indicates fair 

weather.

Finished Barometer

glass container

ruler

clear straw or 

plastic tubing

tape 

gum or clay

tape 
National Oceanic and Atmospheric Administration (NOAA) 67

Science | SERVICE | Stewardship Understand the Earth

Build a Screened Thermometer to Measure Air Temperature 

What You Will Need

r A wooden or plastic box, large enough to hold 

the thermometer and your hygrometer; see 

Step 1 under “How to Do It”

r Thermometer, about 0°F to 120°F

r White paint and paint brush

r Nails, screws, glue, or tape to attach the thermometer to the box

How to Do It

1. The wood or plastic box is supposed to protect 

your weather instruments from wind, rain, 

and direct sun, but still allow air to circulate so the instruments can get accurate 

readings. A box with a hinged lid that can 

be turned on its side is perfect. Turn the box 

on its side, and cut several slots near what is 

now the bottom of the box. Paint the outside 

of the box with white paint, and find a safe, 

shady outdoor location. The north side of 

buildings has the most shade. Try to find a 

location that is three to four feet above the 

ground.

2. Attach the thermometer to the back of the box 

with tape, glue, screws, or nails. The bulb of 

the thermometer should be about two inches 

above the bottom of the box.

Build a Hygrometer to Measure Humidity

What You Will Need

r Piece of wood or Styrofoam about nine inches 

long and four inches wide

r Flat piece of plastic, thin enough to cut with 

scissors; about three inches long and one 

inch wide (an old credit card or laminated 

luggage tag works well)

r Two small nails

r Three strands of human hair, about eight 

inches long

r Dime

r Glue

r Tape

r Hammer

r Scissors

How to Do It 

1. Cut the plastic into a pointer as shown on the 

pattern below.

2. Poke one of the nails through the pointer 

near the base of the triangle. Wiggle the nail 

around until the pointer moves freely and 

loosely around the nail.

3. Tape the dime onto the pointer near the tip of 

the triangle.

4. Glue the hair strands onto plastic between the 

nail hole and the dime.

5. Use a nail to fasten the pointer to the wood or 

Styrofoam base about 3/4 of the way down 

the side. Be sure the pointer can still turn 

freely on the nail.

6. Attach the other nail to the base about one 

inch from the top of the base, in line with the 

spot where the hair is glued to the pointer.

7. Pull the free ends of the hair tight so that the 

pointer is horizontal. Wrap the hair around 

Pointer Pattern
noaa.gov

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68

0

5

10

15

-5

-10

-15

0

5

10

15

-5

-10

-15

the upper nail and glue to hold the hair in 

place.

8. Make a photocopy of the scale and cut it out. 

Glue the scale to the base so that the pointer 

is pointed to the “0” mark. Your hygrometer 

is fi nished!

9. Human hair will expand and lengthen when 

the air is moist, causing the pointer to move 

down. When the air is dry, the hair will 

contract and shorten, causing the pointer to 

move up. Use the scale to record the pointer’s position. Keep your hygrometer in a sheltered location. The box used for the screened 

thermometer is ideal.

Wood or Styrofoam

nail

nail dime

plastic pointer

Hair

Finished Hygrometer
National Oceanic and Atmospheric Administration (NOAA) 69

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

Build a Rain Gauge to Measure Rainfall

What You Need

r Straight-sided glass or plastic container, with 

a diameter of about two inches or less (such 

as an olive jar)

r Coat hanger or wire bent to make a holding 

rack (see picture)

r Measuring spoons: One teaspoon and 1/4 

teaspoon

r Hammer and nails to secure the rack

r Felt tip marker

How to Do It

1. Rain gauges measure the amount of rainfall 

in cubic inches. So your fi rst task is to make 

a scale for your container that shows how 

many cubic inches of water are in the container. One cubic inch of water is about 3 1/4 

teaspoons, so you can draw the scale on your 

container by measuring 3 1/4 teaspoons 

of water to your container, then drawing a 

short line at the level of the water. If you 

look closely, the top of the water will seem 

to be slightly curved and thickened. Draw 

your line so that it matches the bottom of the 

curved surface (which is called a meniscus). 

This line corresponds to a rainfall of one 

inch. 

2. Add another 3 1/4 teaspoons of water to the 

container and draw another line. The second 

line corresponds to a rainfall of two inches. 

3. Repeat Step 2 until you have at least fi ve 

marks on the container. This will be enough 

for most rain events; but you may want to 

add another line or two, just in case!

4. Find a location for your rain gauge where there 

is nothing overhead (such as trees or a building roof) that could direct water into or away 

from your gauge. The edge of a fence away 

from buildings is often a good spot. Another 

possibility is to attach your rain gauge to a 

broomstick driven 

into the ground 

in an open area. 

Be sure to record 

rainfall soon 

after a rain event 

to avoid false 

readings caused by 

evaporation. 

Empty your gauge after each reading, and you are 

ready for the next event!

This activity is adapted from Weather Scope: An Investigative 

Study of Weather and Climate:

http://www.k12science.org/curriculum/weatherproj2/en/

activity1.shtml.

glass container

Finished Rain Gauge

coat hanger or wire

oceanexplorer.noaa.gov/explorations/02fi re/logs/

magicmountain/welcome.html
noaa.gov

Discover Your World With NOAA

70

Be A Citizen Weather Reporter

Could you help save lives with your homemade weather instruments? 

Maybe so!

The National Weather Service Cooperative Observer Program is a network of 

more than 11,000 volunteers who report weather observations from farms, 

urban and suburban areas, National Parks, seashores, and mountaintops. Data 

from volunteer weather observers are used to defi ne the climate of the United 

States and to help measure long-term climate changes, as well as to provide 

real-time information to support forecasts, warnings, and other public service 

programs of the National Weather Service.

The Cooperative Observer Program was offi cially created in 1890, but the history 

of volunteer weather observers is even older. John Campanius Holm recorded the 

earliest known weather observations in the United States in 1644-45. George 

Washington, Thomas Jeff erson, and Benjamin Franklin were also serious weather 

observers. Thomas Jeff erson maintained an almost unbroken record of weather 

observations between 1776 and 1816, and George Washington took his last 

observation just a few days before he died.

An essential part of any weather observing station is a system for keeping accurate records of observations. Here’s how to set up a Weather Journal, and some 

tips for making weather forecasts from your observations!

A young volunteer in Granger, Utah (around 1930) operates a cooperative 

weather station where he observes temperature, precipitation, sky conditions, etc. Courtesy NWS.

What You Will Do

Set up a Weather Journal and record 

regular measurements from the 

instruments in your Weather Station

“The whole point is that person is helping out their neighbors 

by sharing that information”. 

Chad Gimmestad - NWS Senior Meteorologist

From minute 12:18 of episode 1 of 

The Crowd & The Cloud: http://crowdandcloud.org/watch-the-episodes/episode-one
National Oceanic and Atmospheric Administration (NOAA) 71

Science | SERVICE | Stewardship Understand the Earth

What You Will Need

Copies of “Weather Journal Data Form”

How to Do It

At least once each day, record the measurements 

from each of the instruments in your weather 

station. Notice that there are two columns for 

“Barometric Pressure” and “Humidity.” Record 

the readings from your instruments in the “Instrument” columns. The “NWS” column is where 

you can record measurements from your local 

weather office. Comparing the two columns gives 

you a way to convert your instruments readings 

to approximately the same scale used for official 

weather measurements. 

Over time, you should begin to see patterns in 

your data. When the weather changes (it gets 

windy, starts raining, etc.), check your records 

for a day or two before. Was there a change in 

temperature, humidity, or barometric pressure? 

Did the wind direction shift? These kinds of 

changes can give clues about what kind of weather is coming. See “Tips for Amateur Forecasters” 

for more information about these clues.

Tips for Amateur Forecasters

from the National Weather Service

Below is a general summary of wind and barometer indications in the United States. The amateur forecaster should 

modify the table as needed, based on his or her own observations. Barometric pressures in this table are in inches of 

mercury at sea level. If you use local weather reports to calibrate your instruments, you don’t have to worry about this 

because official measurements are converted to sea level before they are reported to the public. A general rule of thumb 

is that atmospheric pressure decreases by one inch of mercury for every 1,000 feet of elevation.

If the Wind is Blowing from and the Barometer is the Probable Weather is

Southwest to Northwest 30.10 to 30.20 and steady Fair with slight temperature change for one to two 

 days

Southwest to Northwest 30.10 to 30.20 and rising rapidly Fair, followed by rain within two days

Southwest to Northwest 30.20 and above and steady Continued fair, with little temperature change

Southwest to Northwest 30.20 and above and falling slowly Slowly rising temperature and fair for two days

South to Southeast 30.10 to 30.20 and falling slowly Rain within 24 hours

South to Southeast 30.10 to 30.20 and falling rapidly Wind increasing in force, rain within 12 to 24 hours

Southeast to Northeast 30.10 to 30.20 and falling slowly Rain in 12 to 18 hours

Southeast to Northeast 30.10 to 30.20 and falling rapidly Increasing wind, and rain within 12 hours

East to Northeast 30.10 and above and falling slowly In summer: rain may not fall for several days

In winter: rain within 24 hours

East to Northeast 30.10 and above and falling rapidly In summer: rain likely within 12 to 24 hours

In winter: rain or snow, with increasing winds

Southeast to Northeast 30.00 or below and falling slowly Rain will continue one to two days

Southeast to Northeast 30.00 or below and falling rapidly Rain, with high wind, followed by clearing within 36 

hours, and by colder temperatures in winter 

South to Southwest 30.00 or below and rising slowly Clearing within a few hours, and fair for several 

 days

South to East 29.80 or below and falling rapidly Severe storm soon, followed by clearing within 24 

hours, and by colder temperatures in winter 

East to North 29.80 or below and falling rapidly Severe northeast gale and heavy precipitation

In winter: heavy snow, followed by a cold wave

Changing to West 29.80 or below and rising rapidly Clearing and colder
noaa.gov

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Want to Do More?

Are you interested in becoming a volunteer 

weather observer? SKYWARN is a volunteer 

program established by NOAA’s National Weather Service and partner groups to identify and 

describe severe local storms. Since the program 

started in the 1970s, information provided 

Weather Journal Data Form

Date Time Temperature Barometric Pressure Humidity Precipitation Wind

 Instrument NWS Instrument NWS Type Amount Speed Direction

by SKYWARN Spotters has helped the National Weather Service to issue more timely and 

accurate warnings for tornadoes, severe thunderstorms, and flash floods. In some areas, 

Spotters also are trained on warning signs for 

earthquakes, landslides, avalanches, volcanic 

ashfall, and coastal hazards such as tsunamis, 

water spouts, and rip currents. See https://www.

weather.gov/skywarn/ for more information.
National Oceanic and Atmospheric Administration (NOAA) 73

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

Tornado in a Bottle

“And then I was enveloped by the freight train roar...as 

I got to the stairs all of the front of the building blew 

in...like a bomb went off, just a huge explosion behind 

me...And then screaming wind...While I was crouched 

under the desk the building was breathing. You could 

feel the floor lift about a foot and then you could feel it 

drop...I thought any second this is going to drop and 

we are all going down to the first floor with the building 

on top of us. I was terrified when the building started 

moving, I thought I’m gonna die...” 

Bill Morgan

Journalist and retired Police Information Offi cer

recalling the tornado that struck Lubbock, Texas on May 11, 1970, 

killing 26 people and injuring hundreds

Tornadoes cause an average of 70 fatalities 

and 1,500 injuries each year. These numbers 

would be much higher without NOAA’s tornado 

warning and research programs. Nationwide 

tornado forecasts and urgent tornado warnings 

are issued by the National Weather Service 

and broadcast over NOAA’s All Hazards Weather 

Radio network, which is the nation’s one-stop 

source for weather and emergency information. 

NOAA’s National Severe Storms Laboratory is 

a leader in tornado-related research, and in 

developing technologies such as Doppler radar 

to improve forecasts and warnings of tornadoes 

and other severe weather.

When you hear the word “tornado” what picture 

pops into your mind? For most people it is the 

funnel-shaped black cloud, with spiralling 

winds called a “vortex.” Here’s how you can 

create your own “tornado in a bottle.”

What You Will Do

Create a vortex similar to the 

wind pattern of tornados

Did you know:

• The 1970 Lubbock tornado was classifi ed as F-5, 

which is the highest a tornado can be rated

• In a typical year about 1,000 tornados will strike the 

United States

• The strongest tornadoes have rotating winds in 

excess of 250 mph

• Tornadoes can be up to one mile wide and may stay 

on the ground for more than 50 miles. 

• Tornados can occur at any time of the year and have 

occurred in every state in the country

• More tornados strike the central United States than 

any other place in the world; which is why this 

area is nicknamed “tornado alley”

The Dimmitt Tornado, 

South of Dimmitt, Texas

Courtesy NOAA.
noaa.gov

Discover Your World With NOAA

74

What You Will Need

❒ Two empty two-liter plastic soda bottles

❒ Tornado Tube plastic connector (available 

from science museums, science stores, 

novelty stores, scientifi c supply companies, 

etc.) - OR

❒ Metal washer, about one inch diameter 

with a 3/8-inch diameter hole, and plastic 

electrical or duct tape

❒ Dishwashing detergent

❒ (Optional) Food coloring

How to Do It

1. Fill one of the two-liter bottles about 2/3 full 

of water. Add three drops of dish soap and a 

couple of drops of food coloring to help make 

the vortex more visible.

2. Screw the plastic connector onto the bottle 

containing the water, then attach the empty 

bottle to the open end of the connector. Or, 

tape two bottles together with a fl at washer 

between them. Use plastic electrical tape or 

duct tape.

3. Turn the two-bottle assembly over, and place 

the assembly on a table with the fi lled bottle 

on top. Watch the water slowly drip down 

into the lower bottle as air simultaneously 

bubbles up into the top bottle. The fl ow of 

water may come to a complete stop. Now, 

rapidly rotate the bottles in a horizontal 

circle a few times. Observe the formation of a 

funnel shaped vortex as the top bottle drains 

much more quickly. You can make the vortex 

with a single bottle by twirling the bottle and 

holding it over a water basin or the ground 

to drain, but you lose the water and have to 

refi ll the bottle each time you use it. Now you 

know how to use a liquid tornado to quickly 

empty a large bottle!

What’s Happening

When the water is not rotating, surface tension 

creates a skin-like layer of water across the small 

hole in the center of the connector or washer. If 

the top bottle is almost full, the weight of the 

water is suffi cient to push out a bulge in this surface to form a large drop, which then drips into 

the lower bottle. As water drops into the lower 

bottle, the pressure in the lower bottle increases 

washer

vortex
National Oceanic and Atmospheric Administration (NOAA) 75

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

until air bubbles are forced into the upper bottle. 

The pressure of the water’s weight at the surface 

of the connector or washer decreases as the 

water level in the upper bottle drops. When the 

water level and pressure decrease enough, the 

water surface can hold back the water and stop 

the fl ow completely.

When you rotate the bottles in a horizontal circle, the water in the upper bottle starts rotating 

as well. As the water rotates, forces called centripetal forces pull the water toward the center 

of the bottle. At the same time, gravity pulls the 

water toward the drain hole. As the water drains 

into the lower bottle, a vortex forms. As water 

particles at the outside of the bottle move toward 

the hole, the speed of the particles increases and 

the centripetal forces increase. The slope of the 

water shows where centripetal forces are increasing. So at the bottom of the vortex, the slope 

of the water is steeper because the centripetal 

forces are increasing as the water moves with 

higher speeds and in smaller circles. The water 

drains smoothly and rapidly because the hole in 

the vortex allows air from the lower bottle to fl ow 

easily into the upper bottle. 

There are many examples of vortices in nature, 

including whirlpools, hurricanes, the Great Red 

Spot on Jupiter, sunspots, and spiral galaxies 

(such as our own galaxy, the Milky Way). Keep 

in mind that while the spiralling motion makes 

many vortices look similar, they occur for many 

diff erent reasons. The vortex in your “bottle 

tornado” is caused by horizontal spin (provided 

by you) and gravity. But a real tornado in the 

atmosphere is caused by a combination of wind 

shear, changes in atmospheric pressure, and 

centrifugal force.

By the way, tornadoes in the atmosphere happen on a relatively small scale (compared to the 

size of the whole atmosphere). This means that 

tornadoes may rotate clockwise or counterclockwise, regardless of where they are on Earth; just 

like your bottle tornado can be made to rotate in 

either direction.

Oldest known photo 

of a tornado. 

August 28, 1884, 

Howard, South Dakota. 

Courtesy NOAA.

Want to Do More?

Find out more about tornadoes at NOAA’s Tornadoes Web page, http://www.noaa.gov/tornadoes.html. You may also want to visit the Tornado 

Project’s Web site, http://www.tornadoproject.

com/.

Portions of this activity are adapted from an Exploratorium 

Science Snack (http://www.exploratorium.edu/snacks/).

Tune In to NOAA Weather Radio

NOAA Weather Radio (NWR) broadcasts local 

weather forecasts 24 hours a day from local 

offi ces of the National Weather Service. NWR 

is an All-Hazards program that broadcasts 

warnings and information about emergencies 

that include:

• natural events such as tornadoes, hurricanes, 

fl oods, and earthquakes;

• technological accidents such as chemical 

spills, oil spills, nuclear accidents; industrial emergencies, shipping accidents, or 

train derailments;

• AMBER alerts; and

• terrorist attacks 

NWR broadcasts cannot be heard on a simple 

AM/FM radio receiver, but the Weather Band 

is built into many automobile radios, walkie-talkies, marine radios, and other receivers. 

Prices for Weather Radio receivers start at about 

$20. Some receivers have a built in alarm that 

is turned on by a special tone sent from NWR 

during an emergency to signal that information 

is being broadcast about a life-threatening 

situation.

For more information about NOAA Weather Radio, visit http://www.weather.gov/nwr/
noaa.gov

Discover Your World With NOAA

76

from a Rip Current Safety Poster by NOAA’s National Weather Service, 

NOAA’s National Sea Grant College Program, and 

the United States Lifesaving Association

(http://www.ripcurrents.noaa.gov/signs/rip_signs-r.pdf)

Rip Currents

“I grew up swimming in the ocean and am very comfortable 

in it. One of my favorite pastimes in the ocean is diving under 

breakers and floating over swells. [Once], I dove under a 

wave... but when I surfaced and looked back over my shoulder, I was way out from the shore. I knew immediately what 

had happened. I tried swimming parallel to the shore, but was 

still in a very strong current and began to tire quickly.

Then a wave broke over my head, and I felt the panic rising. I 

know that panic is one’s worst enemy in the water, so I floated 

and treaded water for a few minutes to catch my breath and relax. ...When I looked out to sea to keep an eye on the swells,...I 

realized that just a little further out, there were surfers.

[So]instead of trying to make it back to shore on my own, I 

turned and swam out to where they were. I told them what had 

happened and asked if one of them would allow me to accompany him into shore using his board as a boogie board for both 

of us. Of course, one of them agreed.

It took both of us to get far enough away from the current so 

we could paddle back into shore. I feel very fortunate that I 

recognized what had happened, knew not to panic, and was 

able to find a solution.”

by Kathryn T. Graham

from the National Weather Service Rip Current Safety Web page

http://www.ripcurrents.noaa.gov/survivor.shtml

• A channel of churning, choppy water

• A difference in water color

• A line of foam, seaweed or debris moving 

out to sea

• A break in the incoming wave pattern

There are three basic safety rules for ocean swimming:

• Swim near a lifeguard

• Never swim alone

• If in doubt, don’t go out

If you are ever caught in a rip current:

• Relax and float, rip currents do not pull you 

under

• Don’t swim against the current

• Swim in a direction following the shoreline, 

or toward breaking waves

• If you need help, call or wave your arms for 

assistance

What You Will Do

Demonstrate why swimmers caught in 

rip currents have to swim following the 

shoreline to escape

Rip currents are powerful, 

channeled currents of 

water flowing away from 

shore. They can occur at 

any beach with breaking 

waves, including many 

Great Lakes. These 

currents are killers. The 

United States Lifesaving 

Association estimates that 

every year, rip currents on 

our nation’s beaches kill 

more than 100 people.

Here are some clues that 

a rip current may be 

present:
National Oceanic and Atmospheric Administration (NOAA) 77

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

What You Will Need

r Two or more strips of ribbon, rope or string, 

each at least ten feet long; if you have a 

choice, a blue color is good for representing 

ocean waves

r At least fi ve people, including yourself

How to Do It

1. Have pairs of participants hold opposite ends 

of the rope or ribbon. You will need at least 

two pairs of participants to do the demonstration.

2. Designate one side of a room or outdoor space 

as the “shore” and the opposite side as “deep 

water.”

3. Have pairs of participants stand so that the 

rope or ribbon is stretched out, and is perpendicular to the shore. These participants 

and their ropes or ribbons represent waves.

4. Place a “trapped swimmer” participant in the 

“current” between two of the “waves.” 

5. Have the “swimmer” walk toward the “deeper 

water,” as if being carried out by the current. 

The “trapped swimmer” can only escape by 

swimming in a direction following the shoreline until she or he is out of the rip current. 

Then he or she can use the waves to return 

safely to the beach.

Want to Do More?

• Find out more about rip currents and other 

beach hazards on NOAA’s rip current Web site 

at www.ripcurrents.noaa.gov.

• In coastal areas, many of NOAA’s National 

Weather Service Forecast Offi ces issue a Rip 

Current Outlook as a part of their Surf Zone 

Forecast. NOAA identifi es days with forecasts 

for particularly dangerous rip currents with 

“High Risk of rip currents.” Visit: http://www.

ripcurrents.noaa.gov/forecasts.shtml to 

learn more.

• NWS National Seasonal Safety Campaign - 

 National Weather Service:

 NOAA NWS Weather Ready Nation Seasonal 

Safety Campaigns have replaced the awareness/preparedness weeks we had with the 

exception of a couple, one being Hurricane 

Preparedness Week. 

 The aim of the National Seasonal Safety 

Campaign is to build a Weather-Ready Nation, 

one that is prepared for extreme weather, 

water, and climate events. With the National 

Seasonal Safety Campaign, we seek to inform 

the public about seasonal weather hazards 

during the time they are most common.

https://www.weather.gov/safetycampaign

Close up of Rip Current

Courtesy of Lifeguard Captain Nick Steers, 

County of Los Angeles Fire Department

Beach View of Rip Current Along Jetty

Courtesy of Dr. Tom Herrington, Stevens Institute of Technology

Rip Current on Grand Avenue Beach

Courtesy of Chris Brewster, USLA
noaa.gov

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78

Be a Tree Ring Detective

The storm took place at sundown, it lasted through the night,

When we looked out next morning, we saw a terrible sight. 

We saw outside our window where wheat fields they had grown

Was now a rippling ocean of dust the wind had blown.

It covered up our fences, it covered up our barns,

It covered up our tractors in this wild and dusty storm. 

We loaded our jalopies and piled our families in, 

We rattled down that highway to never come back again.

~ from “The Great Dust Storm” by Woody Guthrie

Earth’s climate is always changing, and these changes can have large impacts 

on humans. An increase in the number of droughts, fl oods, or hurricanes, for 

example, will cost U.S. citizens billions of dollars and threaten the lives of many 

people. Information on past climate changes can give valuable clues on how to 

plan and prepare for future climate change. Unfortunately, records of human 

weather measurements only go back about 150 years. To really understand 

Earth’s climate change history, we need information that goes back hundreds 

and thousands of years. 

One way to get this kind of information is to study tree rings (the analysis of 

tree rings is known as dendrochronology). As trees grow, their trunks increase in 

length and thickness. Most trees only grow during part of the year (the growing 

season). This starting and stopping of the growth process produces visible 

bands or “rings” of wood around the trunk of the tree. Each ring corresponds 

to one year of growth. The oldest rings are near the center of the tree, while 

the youngest rings are at the outside of the trunk next to the bark. The ring 

just inside the bark is the current year’s growth. There are two kinds of wood 

in each ring: “earlywood” appears light in color and its cells have thin walls; 

“latewood” appears dark in color and its cells have thick walls. The width of the 

rings changes according to the environmental conditions that existed during 

the growing season, so ring width can tell scientists a lot about how climate 

changed during the years when the tree was growing. If the rings are wide, 

then conditions were probably favorable for tree growth. Narrow rings, on the 

other hand, may indicate drought, disease, or other conditions not favorable to 

growth.

Could you be a good Tree Ring Detective? Try solving this puzzle to fi nd out!

What You Will Do

Cross-date tree-ring samples to find out which sample is oldest, 

and then find the age of the oldest sample

Dust storm approaching Stratford, Texas. April 18, 1935

Courtesy NOAA.

Be a Tree Ring Detective
National Oceanic and Atmospheric Administration (NOAA) 79

Science | SERVICE | Stewardship Understand the Earth

What You Will Need

r Copy of “Tree Ring Sample Sheet”

r Blank piece of paper

r Scissors

r Clear tape

Warning

Be careful with scissors!

How to Do It

Most tree-ring samples are collected with a tool 

called an “increment borer.” This is a hollow shaft 

of steel, about 3/16 inch diameter, with a sharp 

threaded bit at the tip. A handle fits into the 

opposite end and is used to turn the borer into 

the tree. When the borer is pulled out of the tree, 

it removes a core of wood that shows the rings. 

Most trees are able to seal the small bore hole 

with sap, so coring does not cause any serious 

damage to most trees that are sampled. 

You might think that you could find the age of a 

tree simply by counting the rings, but it isn’t that 

simple. The problem is that samples taken from 

trees growing in the same area (and even from 

the same tree) usually are not identical. There 

may be “extra” rings in some parts of the tree, 

or missing rings in other parts. To deal with this 

problem, dendrochronologists use a procedure 

called crossdating. This procedure involves comparing and matching the tree ring patterns from 

several trees that have grown in the same area, 

and using statistical methods to find the exact 

year in which the rings were formed. This procedure also allows scientists to compare rings from 

trees that have grown at different times, so the 

age of very old wood samples can be accurately 

determined.

On the next page, there are two sets of tree 

ring samples that can be matched for crossdating. Most tree-ring studies involve many more 

samples and some additional analytical steps 

(check out the resources listed under “Want to Do 

More?”).

1. Cut out each of the tree ring samples.

2. Turn the blank piece of paper so that the longest side is horizontal, and tape the tree ring 

sample from the living tree onto the blank 

piece of paper near the upper right corner. 

3. Find another tree ring sample that matches 

part of the tree ring pattern from the living 

tree. Line up the matching rings and tape the 

sample beneath the sample from the living 

tree.

4. Repeat Step 3 until you have matched all four 

samples.

5. Count how many rings are in the combined samples, starting with the left-hand ring of the 

oldest sample and ending with the ring next 

to the bark of the living tree sample. Be sure 

to count overlapping rings only once.

6. How old is the living tree? How old is the 

oldest tree? Which tree seems to have grown 

under the most stressful conditions? When 

you think you know the answers, check the 

answer box. 

Want to Do More?

NOAA’s Paleoclimatology Web site (https://

www.ncdc.noaa.gov/data-access/paleoclimatology-data) has information on how 

past climates are studied; how climate has 

changed, and how we can plan for future 

climate change.

Visit https://www.ncdc.noaa.gov/data-access/

paleoclimatology-data/datasets/tree-ring to 

learn more about tree rings.

Visit https://www.ncdc.noaa.gov/news/pictureclimate-how-can-we-learn-tree-rings to 

unlock the secret of how trees tell us about 

climate conditions.

Visit https://www.climate.gov/teaching/resources/tree-rings-counting-years-global-warming for a video describing the role dendrochronology plays in understanding climate 

change.

Visit https://www.climate.gov/teaching/resources/signs-change-studying-tree-rings to 

learn about dendrochronology (the study of 

tree rings to understand ecological conditions in the recent past).

http://www.pbs.org/wgbh/nova/vikings/treering.html – Learn how dendrochronology was 

used to study ships of the ancient Vikings.
noaa.gov

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80

Answer Box

DO NOT PEEK!

until you have done

your detective work.... 

Living Tree

bark

Dead Tree A

bark

Dead Tree B bark

Dead Tree C

bark

Sample Set 1

Living Tree

bark

Dead Tree A

bark

Dead Tree B bark

Dead Tree C

bark

Sample Set 2

Tree Ring Sample Sheet

ANSWERS

Sample Set 1 – 

The correct sequence for this set is Living Tree - Dead Tree 

C - Dead Tree A - Dead Tree B. The oldest tree (Dead Tree 

B) is 44 years old. Tree A seems to have grown under more 

stressful conditions than the other trees, since most of its 

rings are close together, indicating slow growth during 

those years.

Sample Set 2 – 

The correct sequence for this set is Living Tree - Dead Tree 

B - Dead Tree A - Dead Tree C. The oldest tree (Dead Tree C) 

is 41 years old. The Living Tree seems to have grown under 

more stressful conditions than the other trees, since more 

of its rings are close together than in the other samples, 

indicating slow growth during those years.

Dust buried farms and equipment, killed livestock, and caused human death and misery in the Great Plains during the height of the 

Dust Bowl years. 1935. Courtesy Historic NWS Collection.
National Oceanic and Atmospheric Administration (NOAA) 81

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

“Fifteen years ago, storms battered the West Coast of the 

United States...There were droughts in Australia, Indonesia, and 

India...Worldwide, 2,000 people died...Economic losses amounted 

to billions of dollars...In Indonesia and Borneo, dry conditions 

fed raging forest fires that consumed hundreds of thousands of 

acres. Smoke blanketed the area...”

~ from the PBS news program, “Bracing for El Niño” 

October 7, 1997

Your Own El Nino What caused these disasters? Just some warm water in the Pacifi c Ocean!

Every two to seven years, trade-winds in the Pacifi c Ocean slow down or reverse 

their direction (no one is sure why). Normally, the Pacifi c trade winds blow 

vigorously towards the west. This causes warm surface water to pile up in the 

western Pacifi c, so that the sea surface is actually about 1/2 meter higher at 

Indonesia than at Ecuador. These winds also cause sea surface temperatures 

to be about eight degrees Celcius higher in the west, with cool temperatures o 

South America, due to an upwelling of cold water from deeper levels. This cold 

water also brings up nutrients that support the growth of marine plants, which 

provide food for major fi sheries. 

But when the trade winds slow down, everything changes. Water temperatures 

become warmer in the eastern Pacifi c and colder in the west. Nutrient upwelling 

slows, and fi sh populations become much smaller along the Pacifi c coast of 

South America. Rainfall follows the warmer water, causing fl ooding in Peru 

and drought in Indonesia and Australia. Changes in the circulation of Earth’s 

atmosphere bring unusual weather to other regions that are far away from the 

tropical Pacifi c. Fishermen in South America noticed that these changes usually 

happen around Christmas time, and named the event “El Niño,” which means 

“the (Christ) Child.”

El Niño isn’t all bad; some of the changes it causes in atmospheric circulation 

can reduce the chances of severe hurricanes in the North Atlantic. But many 

other changes are highly destructive and dangerous, so advance warning of 

El Niño’s approach is extremely important for emergency preparation. NOAA 

satellites are constantly collecting information on sea surface temperatures 

around the globe. NOAA also operates a network of buoys that measure 

temperature, currents, and winds in the tropical Pacifi c Ocean. Every day, 

these buoys transmit data that are immediately available to researchers and 

forecasters around the world.

Here’s a way for you to create a miniature El Niño in your own kitchen!

What You Will Do

Create a working model that shows the 

El Niño effect, trade winds, and upwelling

Virginia National Guard helicopter rescuing an individual from the James River. Note: rescued man 

halfway up to helicopter. Helicopter crewman standing on debris in river. Courtesy NWS Collection.
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82

What You Will Need

❒ Clear plastic rectangular container, about 18 

inches long, four inches high, and four inches deep (such as a food storage container)

❒ Water

❒ Mineral oil, about one cup

❒ Food coloring

❒ Hair dryer

❒ Funnel

❒ Red oil-based paint, about one ounce (two 

tablespoons)

Warnings

Have an adult help with the hair dryer, and be 

careful with any electrical appliance around 

water! Follow warnings on the paint container 

label concerning ventilation and handling.

How to Do It

1. Fill the plastic container with water to within one inch of the top.

2. Add food coloring to the water. Blue is good, 

since we’re dealing with the ocean. Allow 

some of the food coloring to settle to the 

bottom so you can demonstrate upwelling.

3. Pour the mineral oil into a dish and mix in 

one to two tablespoons of the red paint. 

4. Hold the funnel so that the narrow end is 

against the side of the container, just above 

the surface of the water. Gently pour mineral 

oil through the funnel onto the surface of 

the water.

5. The liquids in the plastic container represent 

the warm layer of surface water (the mineral 

oil) and the cold deep water (colored water) 

in the Pacifi c Ocean. Turn on the hair dryer 

and point it into one end of the container. 

This end represents the eastern side of the 

Pacifi c Ocean. Notice that the “warm” water 

piles up in the western end of the container. 

This is the normal condition for the Pacifi c 

Ocean near the equator. If your food coloring 

contained sediment particles, you may see 

these moving upward toward the water surface at the eastern end of the container—just 

like upwelling in the eastern Pacifi c!

6. Turn o the hair dryer, and watch what happens when the trade winds stop.

Want to Do More?

You can fi nd out more about El Niño at:

• NOAA’s Climate Prediction Center Web site 

 www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml

This activity was adapted from “Make Your Own El Niño 

in the Classroom,” https://sealevel.jpl.nasa.gov/

fi les/ostm/make-your-own-el-nino.pdf, by Kelly Perry 

(Jet Propulsion Laboratory), Johan Berlin (Raytheon 

Corporation), James Kendall (Jet Propulsion Laboratory), and Ruby Krishnamurti (Florida State University) 

presented on NASA’s Jet Propulsion Laboratory Education Web page (https://www.jpl.nasa.gov/edu). Plastic container

• NOAA’s El Niño Web page climate.gov/

enso

• The El Niño story page www.pmel.noaa.

gov/elnino/what-is-el-nino

• NASA’s Jet Propulsion Laboratory Web 

site www.jpl.nasa.gov/climatesciences/projects/enso/index.html
National Oceanic and Atmospheric Administration (NOAA) 83

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Please Pass the Salt

“Antarctica is the coldest, driest, windiest continent on the planet. Temperatures can plummet to 

-58°F, which is 90°F below freezing...Antarctica is 

so cold that most of the ice there never melts; 

the continent is permanently covered in ice. Yet, 

Weddell seals can live there...because some water 

remains unfrozen, and they can dive and re-surface 

through these holes in the ice. How do these holes 

stay open?...The answer is, it’s a joint effort between the seals and the properties of the water.”

~ from the Web site of Dr. Terrie M. Williams, Professor,

Ecology and Evolutionary Biology, University of California Santa Cruz

http://bio.research.ucsc.edu/people/williams/teachers/intro.htm

What is the most obvious property of seawater? It’s salty! But if you mix 

salt from your kitchen into a glass of water, it doesn’t taste exactly like 

seawater. That’s because seawater contains many other chemicals in addition to sodium chloride (which is ordinary kitchen salt), such as magnesium sulfate, magnesium chloride, and calcium carbonate. Scientists 

call the content of all dissolved salts in seawater “salinity,” and measure 

it in parts per thousand (abbreviated ppt or ‰), which is equivalent to 

grams per kilogram. Freshwater has a salinity of 0‰; normal seawater 

has a salinity of about 35‰. 

Salinity makes seawater very di erent from freshwater. Most animals 

have a specifi c range of salinities that they can tolerate, and cannot 

survive if the salinity is above or below their tolerance range. Changes in 

salinity can a ect the circulation of the oceans, and may even a ect climate. Because salinity infl uences our environment in many ways, NOAA 

keeps track of salinity in many places along the U.S. coasts and around 

the world. Here are some experiments you can do to discover some of the 

most important properties of seawater.

A Weddell Seal at a breathing hole. Courtesy NOAA Corps Collection

Photographer: Giuseppe Zibordi. Credit: Michael Van Woert, NOAA NESDIS, OAR

What You Will Do

Experiment to find some of the ways that salt 

changes the physical properties of water

Please Pass the Salt
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What You Will Need:

❒ Salt

❒ Water

❒ Freezer

❒ Tablespoon measure

❒ Cup measure

❒ Spoon for stirring

❒ Five clear plastic cups, six ounces or larger

❒ One fresh egg

❒ Food coloring

How to Do It:

1. For your fi rst experiment, dissolve three 

tablespoons of salt in one cup of water. Pour 

the salt solution into one of the plastic cups 

until the cup is about 3/4 full. Pour the same 

amount of fresh water into another cup. Place 

both cups in a freezer. Check the cups every 

half hour for two hours. Which solution freezes 

fi rst? What has happened to the salt solution 

after 24 hours?

2. For the second experiment, dissolve three 

tablespoons of salt in one cup of water, and 

pour the salt solution into one of the plastic cups until the cup is about half full. Fill 

another cup about half full of fresh water, 

and add a few drops of food coloring. Now, 

carefully pour the colored fresh water into 

the cup of salt water, holding the edges of 

the cups together so that the fresh water 

fl ows down the inside of the cup containing 

the salt water. Do the two solutions mix, or 

does one fl oat on top of the other? Which 

solution has the greater density?

3. Finally, pour fresh water into a plastic cup 

until the cup is about 3/4 full. Carefully crack 

a fresh egg, and gently drop the contents of 

the egg into the cup. If your egg is fresh, the 

yolk will be a fi rm but fl exible sphere that 

sinks to the bottom of the cup. If your egg 

is not-so-fresh, the yolk will break or ooze 

into the water and your experiment is over! 

Assuming the egg yolk is still intact, add two 

tablespoons of salt to the water, and gently 

stir with a spoon. Over the next few minutes, 

the salt will slowly dissolve. What has happened to the egg after ten minutes?

 Now, do you have an idea why holes the Antarctic ice stay open and don’t immediately 

freeze over?

What’s Going On Here?

Pure water freezes at 32°F (0°C), but adding salt 

lowers the freezing point of pure water. This is 

why salt is sometimes used to keep ice from forming on sidewalks. When water freezes, it forms 

crystal-like structures. When salt water freezes, 

only the water forms these structures; the salt is 

An iceberg in Gerlache Strait, West Antarctica

Photographer: Rear Admiral Harley D. Nygren, NOAA Corps (ret.) Courtesy NOAA.
National Oceanic and Atmospheric Administration (NOAA) 85

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

left out in unfrozen water. So as salt water freezes, the water that is not frozen becomes saltier.

After 24 hours in your freezer, the cup containing 

fresh water should be frozen solid (if it isn’t, your 

freezer isn’t working!). The salt solution probably contains some ice, but it is not frozen solid. 

It may appear slushy, and you should have no 

trouble sticking your fi nger through whatever ice 

is in the cup.

Salt water is more dense than freshwater, so 

freshwater fl oats on top of salt water. The greater density of salt water also means that objects 

fl oat more easily in salt water than in freshwater. 

Remember Archimedes’ Principle, which says that 

an object in a fl uid is buoyed up by a force equal 

to the WEIGHT of the fl uid displaced by the object 

(see Page 11). One cup of salt water weighs more 

than one cup of fresh water, so its buoyant force 

is greater. So your egg (if it was fresh) sank in 

freshwater, but was buoyed up by the salt water.

Want to Do More?

1. Check out NOAA’s National Ocean Service at 

www.oceanservice.noaa.gov/education/kits/

estuaries/media/supp_estuar10c_salinity.

html and www.oceanservice.noaa.gov/education/kits/estuaries/estuaries05_circulation.html to fi nd out more about salinity and 

how it a ects coastal ecosystems.

2. Other NOAA programs that provide information 

on salinity include:

• The Regional Ocean Forecast System (nsidc.

org/cryosphere/seaice/characteristics/

brine_salinity.html), which provides 

information on salinity and brine; 

• The National Oceanographic Data Center 

(www.nodc.noaa.gov/) with records of 

global ocean salinity data; and 

• The National Estuarine Research Reserve 

System (coast.noaa.gov/estuaries/science-data/) that uses automatic instruments to collect data on salinity and other 

physical features. 

NOAA wildlife biologists Mike Goebel and Birgitte McDonald get a Southern elephant seal ready for measurement and tagging, as 

part of the U.S. Antarctic Marine Living Resources research program that provides scientifi c information needed to conserve and 

manage marine living resources in the oceans around Antarctica. Courtesy NOAA/Scott Seganti.
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86

Satellite Communications

Graphic of 2nd generation GOES satellite in orbit. Courtesy NOAA.

What...

• has helped rescue more than 41,000 people since 1982;

• shows the location of fi res, snow cover, thunderstorms, and erupting 

volcanoes everywhere on Earth;

 • lets you watch the lights go on all over North America as the sun sets?

Satellites, of course! But what keeps satellites in place? And how do they 

help send information all over the world? Here are two simple demonstrations that answer these questions.

What You Will Do

Demonstrate two of the basic principles 

that make satellites useful
National Oceanic and Atmospheric Administration (NOAA) 87

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

What You Will Need

r Empty three pound coff ee can

r Poster board, at least 22-inches square

r String, about 12 inches long

r Pencil

r Scissors

r Marble

r Masking tape

r Flashlight

r Mirror

r Sheet of light-colored paper

r Two rooms connected by a doorway

r A partner

Warnings

Be careful with sharp scissors!

How to Do It

To show how satellites stay in orbit:

1. Tie one end of the string around the pencil. 

Hold the other end near the center of the 

poster board, and draw a circle about 22 

inches in diameter.

2. Cut the circle out of the poster board, then cut 

a wedge (pie shape) that is 1/8 of the circle.

3. Overlap the two edges of the circle where the 

wedge was removed to form a cone, and tape 

the edges together so that the cone holds its 

shape.

4. Put the pointed end of the cone in the coff ee 

can, and tape the cone to the sides of the 

can.

5. Roll the marble around the inside top of the 

cone as fast as possible, and observe the 

movement.

 When you push the marble forward and 

release it, the cone applies a continuous 

resistance to the marble’s movement and 

causes it to move in a circle. As the speed of 

the marble decreases, the gravity pulls the 

marble down to the bottom of the cone. If you 

could keep the marble moving at a constant 

speed, it would resist the pull from gravity 

and continue circling in the same place. When 

a satellite is launched, it moves away from 

Earth. Gravity causes a continuous pull on 

the satellite that keeps it from continuing to 

move out into space. Instead, the forward 

motion of the satellite keeps it moving in a 

circle around the Earth. 

To show how satellites help send messages 

between two points on Earth:

1. Have your partner stand in one room facing 

the doorway and holding a piece of paper. 

Your demonstration will work best if your 

partner is about six feet away from the wall 

that has the doorway.

2. Set up a mirror near the doorway in the other 

room so that the mirror is angled toward the 

doorway.
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3. Shine a fl ashlight toward the mirror. The light 

will refl ect into the other room so that your 

partner can catch it on the piece of paper.

The light is like messages containing information 

about Earth’s oceans, atmosphere, ecosystems, 

the location of people needing rescue, etc. These 

messages can be sent to satellites that relay the 

information to other locations on Earth that are 

thousands of miles away. 

Before satellites were available, messages were sent 

by bouncing radio signals off of Earth’s atmosphere. 

But because the atmosphere is constantly changing, 

radio signals don’t always bounce to the place that 

the sender wants them to go. Satellites are above 

Earth’s atmosphere, and are a much more reliable 

way to communicate.

There are two types of satellites. Geosynchronous 

satellites are about 22,240 miles above the 

equator, and travel at a speed (about 6,800 miles 

per hour) that matches the Earth’s rotation. 

This allows them to hover continuously over 

one position on the surface. Because they 

stay above a fi xed spot on the surface, they 

provide a constant lookout for the atmospheric 

conditions that trigger severe weather events 

such as tornadoes, fl ash fl oods, hail storms, and 

hurricanes. Polar orbiting satellites circle the 

Earth 14 times a day, at an altitude of about 500 

miles. These satellites pass almost directly over 

the North and South Poles, and view all regions 

of the Earth in a single day.

Want to Do More?

1. Visit http://www.goes-r.gov/resources/

education.html for resources designed to 

educate customers about meteorology, 

space science, earth observing systems, and 

benefi ts satellites will provide

2. Visit www.nesdis.noaa.gov/content/our-satellites to learn about our satellites, the 

history, how they work, upcoming launches, 

and how our satellites are part of a worldwide constellation that supports forecasting 

around the globe.

3. See www.bu.edu/satellite/classroom/model.

html for directions for making a model of an 

artifi cial satellite.

4. See www.sarsat.noaa.gov/sys-diag.html for 

information about how satellites are used for 

search and rescue.

Graphic of the Synchronous Meteorological Satellite, a geosynchronous satellite that was the forerunner of the GOES (Geostationary 

Operational Environmental Satellite) satellites. Courtesy NOAA.
National Oceanic and Atmospheric Administration (NOAA) 89

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

Wooly Magma

Descend into the crater of Yocul of Sneffels, which the 

shade of Scartaris caresses, before the kalends of July, 

audacious traveler, and you will reach the center of the 

earth. I did it.

“All scientific teaching, theoretical and practical, 

shows it to be impossible,” I said.

“I care nothing for theories,” retorted my uncle.

“But is it not well-known that heat increases one 

degree for every seventy feet you descend into the earth? 

Which gives a fine idea of the central heat. All the matters 

which compose the globe are in a state of incandescence; 

even gold, platinum, and the hardest rocks are in a state 

of fusion. What would become of us?”

“Don’t be alarmed at the heat, my boy.”

“How so?”

“Neither you nor anybody else know anything 

about the real state of the earth’s interior. All modern 

experiments tend to explode the older theories.”

~ from A Journey to the Center Of the Earth, by Jules Verne

jv.gilead.org.il/vt/c_earth/

Most of what Jules Verne wrote about the 

center of the Earth in 1864 is now considered 

to be wrong. While it is still true that no one 

has actually seen the Earth’s interior, today’s 

“scientifi c teaching, theoretical and practical” 

agrees more with young Harry than with his 

adventurous uncle. The center of the Earth is 

now believed to have an average temperature 

of 7,000°F, with maximum temperatures as 

high as 13,000°F. Here’s a way to show what 

scientists think we might fi nd if we could really 

take a journey to the center of the Earth.

What You Will Do

Make a colorful model of Earth’s structure

Most of what Jules Verne wrote about the 

center of the Earth in 1864 is now considered 

to be wrong. While it is still true that no one 

has actually seen the Earth’s interior, today’s 

agrees more with young Harry than with his 

adventurous uncle. The center of the Earth is 

now believed to have an average temperature 

of 7,000°F, with maximum temperatures as 

high as 13,000°F. Here’s a way to show what 

scientists think we might fi nd if we could really 

take a journey to the center of the Earth.

Wooly Magma

Overfl ow from Mauna Ulu Crater. View east at overfl ow from 

trench into main Mauna Ulu crater on March 19, 1972. Note 

partially cooled skin on lake. Photo credit: R.T. Holcomb, Hawaiian 

Volcano Observatory, U.S. Geological Survey.
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What You Will Need

r Two containers that will each hold about eight 

quarts (pots or bowls are fine)

r Paper towels 

r Hand towel 

r Dishwashing liquid

r Sharp scissors 

r Serrated knife and a cutting board 

r Rubber ball, about 1-1/4 inches diameter

r Wool roving in six colors; about 2/3 ounce of 

each color (red, gold, pink, green, white, and 

blue are suggested, but any colors will work)

r Hot and cold tap water

r Ice (about seven pounds)

Warnings

1. Be careful with scissors and hot water!

2. Get help from an adult to use the serrated 

knife!

How to Do It

To make your model, you will use a process called 

“felting.” You can read more about felting and 

how it works under “What’s Happening” at the 

end of this section.

1. Here is a drawing that shows the layers of 

Earth’s structure that will be included in your 

model. Since no one has actually seen Earth’s 

interior, we don’t know what the true colors 

are. So for your model, choose some colors 

that you like, and that are different enough 

so that the layers can be easily seen.

2. Begin constructing your model with the rubber ball, which represents the INNER CORE. 

Wrap a piece of red wool roving around the 

ball. The red roving represents the OUTER CORE. Be sure to wrap the wool roving 

tightly, and try to switch directions as often 

as possible. Pull the fiber as thin as you can. 

When you’ve reached the end, pull the fibers 

out to be as light and transparent as cotton 

candy; smooth those ends over the ball by 

stretching and patting them into place so 

they neatly stick to the ball. This will make 

the felting process easier because the fibers 

can be interlocked better that way.

3. Fill one of the containers about 2/3 full with 

hot tap water (the water should be as hot 

as your hands can stand). Fill the other 

container about 1/2 full with ice, then 

add cold tap water until the container is 

about 2/3 full.

4. Now for the felting! Dunk your woolen ball into either the hot or ice cold 

water. Hold the ball under the water 

and squeeze it hard to make sure water 

penetrates all the way to the inner core 

ball. Lift the woolen ball out of the water 

and squeeze again. Put a couple of drops 

of dishwashing liquid on the woolen ball, 

and roll the ball in your hands lightly, quickly and evenly. After the fibers 

have joined, begin to slightly increase 

pressure. The harder and faster you roll, the 

faster the felting process takes place.

5. After about a minute, dunk the ball into the 

other water container (so if you dunked it in 

cold water first, dunk it in hot water now.) 

The change of temperature shocks the wool 

fibers and makes them cling together.

6. Repeat the rolling process, adding more 

dishwashing liquid only if you need to. Too 

much soap will make the ball slippery and 

hard to press against. If the ball gets too 

soapy, rinse or blot off the excess dishwashing liquid with a paper towel. After about 5 

Inner Core

Outer Core

Mantle

Transition Zone

Asthenosphere

Lithosphere

Structure of the Earth

Crust
National Oceanic and Atmospheric Administration (NOAA) 91

Science | SERVICE | Stewardship Understand the Earth

minutes, you should have a hard, tight ball. 

Now you are ready to add the next layer. 

7. Wrap the gold-colored roving around the ball 

to represent the lower Mantle layer. Remember to wrap the wool tightly, roll it in different directions, pull the end fibers out to be 

very thin, and smooth those ends over the 

ball.

8. Repeat Steps 4, 5, and 6. 

Are you feeling tired? Felting is hard work – if 

you’re not feeling your muscles, you’re not 

working hard enough! 

9. Wrap pink roving around the ball to represent 

the Transition Zone, remembering to wrap 

the wool tightly, roll it in different directions, pull the end fibers out to be very thin, 

and smooth the ends over the ball.

10. Repeat Steps 4, 5, and 6. 

11. Next, add a layer of green roving to represent 

the Asthenosphere. You guessed it —Repeat 

Steps 4, 5, and 6. 

12. Only two layers to go! Wrap the white roving 

around your ball to represent the Lithosphere, and repeat Steps 4, 5, and 6. 

13. At last! It’s time to add the final layer to 

represent the Crust. This could be blue, 

since most of Earth’s surface is covered with 

water, or multi-colored to represents both 

continental and oceanic crusts. Wrap the last 

piece of roving and repeat Steps 4, 5, and 6.

14. When you have finished your model, the 

felted wool ball should feel as firm as a 

tennis ball. Now, ask your adult partner to 

cut around the globe with a serrated knife 

to open the model up. WARNING—Be sure 

to ask your partner not to cut all the way 

through! Leave a hinge area about 1/2 inch 

wide, or the whole thing will fall apart! 

Carefully pull your model open and remove 

the ball. Trim any loose ends with scissors 

to make it uniform and smooth. Put the ball 

back in and ADMIRE your Wooly Magma—it’s 

yours and it’s unique! No two are alike.

What’s Happening

More about Felting

What is felt? Do you know what it is made of? 

Have you ever seen someone throw a pair of 

woolen socks or a wool sweater in the washing 

machine and then the dryer? What happens to it? 

It shrinks! Almost anything made of 100% natural fiber can be felted. During felting, the tiny 

fibers that make up the wool interlock; tightening and closing the small holes that are also part 

of its make up. The felting process is basically a 

compacting of the material that makes the fibers 

very dense. 

Three things are needed to felt wet/moist wool: 

ALKALINITY, HEAT, and AGITATION. In short AHA! 

Any two of them together will lead to a natural 

fiber or fabric felting. If you have a dog, cat, 

rabbit, or other pet with long fine hair, you’ve 

probably noticed mats or clumps behind its ears 

or on the body wherever the hair is exposed to 

AGITATION and moisture. That’s felt! If you’ve 

shampooed those spots on your animal, you’ll 

notice how hard and dense those clumps of fur 

become. That’s because you’ve added the ALKALINITY and intensified the felting process. 

To make your model, you use your muscles and 

a lot of “elbow grease” for the AGITATION. The 

HEAT part comes in when you shock your wool 

by dunking it into ice cold water and then in hot 

water. Dishwashing liquid provides the needed 

ALKALINITY for the process. 

Why would people want to make felt on purpose? 

It can be beautiful and decorative, but more important, it is much warmer than a loosely woven 

garment. It can become nearly impenetrable; 

almost waterproof, and was especially important 

for the people who lived in the day when there 

were no synthetic fibers like nylon, polyester, or 

acrylic that our winter garments are made of now. 

More About Earth’s Layers

Earth’s CORE is made out of iron and nickel and is 

about 1,550 miles in diameter. The temperature 

of the INNER CORE is on average about 7,000 degrees Fahrenheit, but it can go up to 13,000 degrees Fahrenheit. To give you an idea of how hot 

that is, you can bake a loaf of bread in your oven 

at 350 degrees and rock begins to melt at 1,600 
noaa.gov

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92

degrees. Under the immense pressures in 

the INNER CORE, the metals do not fl ow as 

a liquid despite the high temperatures, but 

behave and vibrate like a solid.

The OUTER CORE is a sphere of iron and 

nickel, under less pressure than the inner 

core and nearly as hot. Here the metals 

are in a liquid state; between 4,000 and 

9,000 degrees Fahrenheit. The Outer Core 

is 1,400 miles thick, located about 1,800 

miles beneath the crust. Scientists believe 

that the circulation of an electric current 

in the Outer Core causes the Earth’s magnetic fi eld. 

The MANTLE is Earth’s largest layer, and is 

approximately two thirds of Earth’s total mass. It 

is divided into several parts. The LOWER MANTLE 

(our gold layer) is very dense and hot (4,000 

degrees Fahrenheit).

The TRANSITION ZONE divides the lower mantle 

from its upper portion. The Transition Zone starts 

at a depth of 250 miles and is roughly 190 miles 

thick. The temperatures here are much cooler 

than the lower mantle, around 1,600 degrees 

Fahrenheit.

The ASTHENOSPHERE is in the upper region of the 

mantle, and is the part that fl ows like asphalt. It 

both moves the plates of the Earth and permits 

their motion. This ability of a solid to fl ow is 

called “plasticity”.

The LITHOSPHERE is a slab about 45 miles thick 

in which the continents are embedded. It gives 

us mountains and trenches (collisions), seafl oor 

spreading and new oceans (separation), and long 

earthquake faults, like the San Andreas Fault 

(sliding side-by-side). This zone is composed of 

rigid, brittle rock.

The EARTH’S CRUST is the thinnest layer of the 

Earth at only 3-5 miles thick under the oceans 

and about 25 miles thick under the continents. It 

is composed of two basic rock types: granite and 

basalt. The CONTINENTAL CRUST is mostly granite 

while the OCEANIC CRUST consists of a volcanic 

lava rock called basalt. Temperatures vary from 

air temperature to 1,600 degrees Fahrenheit. It is 

here that volcanoes are started and where we fi nd 

rich soil, jewels, and rocks. We live on the 

Earth’s Crust.

Please note that the layers we use in this 

project are not in scale to the Earth’s 

real layers. They are too similar in size. 

Also, the colors have nothing to do with 

how the Earth looks underneath. No one 

really knows what the layers look like. 

We’ve used color just for fun and to make 

a contrast so we can pick out each layer 

more easily.

Want to Do More?

For more information about Earth and its structure, visit:

pubs.usgs.gov/gip/dynamic/inside.html

www.windows2universe.org/?page=/earth/Interior_Structure/overview.html

www.pbs.org/wnet/savageearth/hellscrust/index.html?pagewanted

This activity was created by Annie Reiser, Global Systems 

Division Visitor Information Specialist at NOAA’s Earth System 

Research Laboratory

Two automobiles are all that remain after this section of Royal Gardens subdivision 

was overrun by lava (October 7, 1987). During October the footpath from a road into 

the housing area was covered, cutting residents off from the few homes that remained. 

Photo credit: J.D. Griggs, Hawaiian Volcano Observatory, U.S. Geological Survey
National Oceanic and Atmospheric Administration (NOAA) 93

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

Survey Mark Hunting

National Geodetic Survey Satellite 

Triangualtion Program, illustrating the idea 

of modeling the Earth. 

Courtesy NOAA Geodesy.

Imagine bridges not meeting in the middle...

Airplanes landing next to runways instead of on them...

Ships frequently running aground...

This is just a glimpse of life without geodesy. 

What’s geodesy? It’s the science of measuring the size and shape of the Earth 

and accurately locating points on the Earth’s surface (and is pronounced “gee - 

ODD - ess - ee”). 

READ ON, and fi nd out how geodesy can be a lot of fun!

Another way to think about geodesy is to imagine a world globe with a lot of 

pins stuck in it. Geodesy is about giving each of those pins its own “address” 

written as latitude and longitude. Why is this important? Because each of those 

pins can serve as a starting point for describing the location of any other point 

on Earth; just like when you want to tell someone how to get to your house, 

you give them a starting point that they know, like a road or a building. In the 

United States, these reference points are developed and maintained by NOAA’s 

National Geodetic Survey (NGS). 

Hang on, we’re almost to the fun stuff !

So where are all those pins stuck in the globe? They are everywhere—more than 

1,200,000 in the United States!

Of course, they really aren’t pins. Instead, NGS uses permanent marks called 

“survey marks” (you may hear survey marks called “benchmarks,” but benchmarks are only one type of survey mark). Often, survey marks are marked with a 

metal disk like the photo below, set in concrete or bedrock:

Survey marks can also be stainless steel rods driven 

into the ground, drill holes in bedrock, bottles, pots, 

or landmarks visible from a long distance, such as a 

water tower, a radio mast, or a church steeple.

What You Will Do

Get information on the location and description 

of survey marks in your geographic area, and find 

out how to share your survey marking discoveries 

with the rest of the world! Courtesy NOAA Geodesy Collection
noaa.gov

Discover Your World With NOAA

94

Now for the fun:

Although the majority of benchmarks are located in 

plain sight, they are usually ignored by the general 

public. Many benchmarks haven’t actually been 

visited in a long time, and no one knows whether 

or not they still exist. So if you find one of these 

benchmarks, so you may actually be rediscovering 

long-neglected objects of American history!

Searching for survey marks is called “mark recovery” 

and is a lot like a treasure hunt (you may hear this 

activity called “benchmarking” but the correct term 

is “mark recovery”). Hunting for survey marks can 

lead to interesting places like high mountain peaks, 

deep woods, old buildings, bridges, and sometimes, 

ghost towns! You can enjoy the excitement of being 

the first to find and document a long-lost survey 

mark; write a log for your discoveries on the worldwide web; and if you find a survey mark that hasn’t 

been recovered in a long time, you can submit a 

recovery note, with your name, to the NGS web site. 

Hunting for survey marks can be even more fun if 

you have a global positioning system (GPS) receiver. 

With GPS, you can go very close to the exact latitude 

and longitude of survey marks installed in your 

area. This is a kind of treasure hunt called “geocaching” (pronounced “GEE - oh - cashing”). 

Here’s how can you find out about survey marks in 

your area, and try your survey mark hunting skills!

What You Will Need

r Computer with internet access

r (Optional) Digital camera (or phone) for photographing your discoveries

r (Optional) GPS receiver (this is useful for 

getting close to a specific survey mark, but 

the actual “find” is usually done by using 

very detailed location descriptions from the 

survey mark’s datasheet)

Warnings

1. Mark recovery should ONLY be done with an 

adult partner!

2. Many survey marks are on private property, 

and may be in dangerous areas. Be sure to 

obey local laws!

How to Do It

1. TThe first step is to find out what survey marks 

are located in your area. The easiest way to 

do this is to use the search engine on the 

National Geodetic Survey website at www.ngs.

noaa.gov. Click on “Survey Mark Datasheets” 

at the left side of the page. This will open the 

“Data Explorer” search engine. The “Getting 

Started” panel has detailed instructions for 

using the search engine. To find survey marks 

in your area:

a. Enter the county, city, or zip code for your 

area in the “Go To Location” menu, then 

click “Go”.

b. The map will zoom in to the area you 

specified. Colored squares show the 

general location of survey marks (if there 

are no squares, there are no marks in 

the specified area). You can change the 

radius of the area using the “Location 

radius” box. Click on one of the squares 

to zoom in further to show individual 

survey marks.

c. Click on one of the survey mark icons, and 

a summary window will pop up. Click on 

“Datasheet” at the bottom of the popup 

window to open the complete datasheet 

for the survey mark you selected.

d. Near the bottom of the Datasheet is a section titled “Station Description,” which 

may be followed by one or more sections 

titled “Station Recovery.” The “Station 

Description” section gives very precise 

instructions for finding the survey mark, 

starting from easy-to-find landmarks 

(such as a public building or the intersection of major roads). This description 

also includes information about things 

that may make it easier to find the survey mark, such as:

“30 FEET SOUTH OF THE CENTER LINE OF 

THE ROAD, 23.98 FEET WEST OF BENCH 

MARK 33 A (USGS), AND ABOUT 2 FEET 

LOWER THAN THE ROAD.”

or

“8 FEET SOUTHEAST OF A GATE IN AN 

EAST-AND-WEST FENCE, AND IN THE TOP 

OF A LAVA ROCK. A UNITED STATES GEOLOGICAL SURVEY STANDARD COPPER NAIL 

AND WASHER, STAMPED 5240.4.”
National Oceanic and Atmospheric Administration (NOAA) 95

Science | SERVICE | Stewardship UNDERSTAND THE EARTH

 The “Station Recovery” section gives 

information about the condition of the 

survey mark at various times when the 

mark location was visited. This section 

can be very important, because sometimes it says that the mark was not 

found. This information can save you a 

lot of time spent looking for a mark that 

no longer exists!

2. Now see whether you can locate some benchmarks. Read the location descriptions 

carefully, and try to start in areas that are 

familiar. BE SURE TO DO THIS ONLY WITH AN 

ADULT PARTNER!

 When you fi nd a benchmark, you can take 

pictures, but that’s all! Never disturb or move 

a benchmark, even if it appears to have been 

damaged. Remember that benchmarks are 

important, they are public property, and are 

protected by law. 

 You can also log your fi nd on the geocaching 

Web site. See www.geocaching.com/mark for 

instructions.

 If the location for survey marks is described 

as something like a radio tower, church 

steeple or smokestack, the top of these 

structures is usually the survey point. Do not 

climb these structures! Just log your fi nd, 

and take the structure’s picture (from the 

ground!) if you have a digital camera.

Members of a 1922 geodetic survey expedition. Until recent advances in satellite technology, namely the creation of the Global Positioning System (GPS), geodetic surveying 

was an arduous task best suited to individuals with strong constitutions, and a sense of 

adventure. Courtesy NOAA NOS Geodesy.

Want to Do More?

You can fi nd out more about geodesy at NOAA’s 

National Ocean Service Web site:

oceanservice.noaa.gov/education/tutorial_geodesy/lessons/global_pos_tutor.pdf

The offi cial geocaching Web site www.

geocaching.com/play has lots more about mark 

recovery and geocaching.
noaa.gov

Discover Your World With NOAA

96

Courtesy Todd Marsee, Michigan Sea Grant

Courtesy Doug Helton, NOAA

Courtesy Laurel Jennings, NOAA

Courtesy Doug Helton, NOAA Courtesy Laurel Jennings, NOAA

Courtesy Jean Kenyon, NOAA Courtesy Victor Lundquist, NMFS-AFSC
National Oceanic and Atmospheric Administration (NOAA) 97

Science | Service | STEWARDSHIP PROTECT THE EARTH

I

n addition to exploring and understanding 

the Earth, NOAA programs are also concerned with protecting Earth’s ecosystems. 

Here’s a little challenge: How many benefi ts 

can you think of that depend on oceans and 

coasts? Next, how many things can you think 

of that might damage oceans and coasts? 

Your list of benefi ts should include food, 

habitat for thousands of plants and animals, 

marine transportation, fi shing, tourism 

and recreation, and places for communities 

(more than half of the U.S. population lives 

and works within 50 miles of the coast). Your 

list of threats may include pollution (many 

kinds), habitat destruction for development 

(many types), storms, and climate change.

NOAA’s mission is to fi nd ways to enjoy the 

benefi ts of oceans and coasts and at the 

same time protect and restore these resources for future generations. NOAA programs 

include protected areas, endangered species, 

fi sheries, pollution control, and projects to 

restore damaged resources. Volunteers are an 

important part of many of these projects. In 

fact, the key to protecting Earth’s Ecosystems 

is public understanding and action. YOU CAN 

HELP PROTECT THE EARTH BY TEACHING 

OTHER PEOPLE ABOUT EARTH’S ECOSYSTEMS!

The more you know, the more you can do! The 

activities in this section will give you some 

tools for teaching other people about what 

EVERYONE can do to help protect the ecosystems that sustain life on Earth.

Courtesy NOAA

PROTECT the Earth Courtesy Caroline Rogers, USGS Courtesy Todd Marsee, Michigan Sea Grant

Courtesy Tony Perry, NOAA 

Courtesy Kathy Crane, NOAA 
noaa.gov

Discover Your World With NOAA

98

Humans have relied on the ocean for 

longer than recorded history. Humans eat 

many species of marine fi sh, so we want 

to know the number of fi sh in parts of the 

ocean available for us to catch. This is a 

big reason why scientists are interested in 

estimating ocean populations.

The ocean covers 70% of the earth and 

contains many diff erent habitats. Even in 

the open ocean, the diff erence in sunlight 

and temperature between the surface and 

500 feet deep is enough to make diff erent 

habitat for diff erent species. Some animals 

like it warm and sunny at the surface, but others like it cold and dark where it is 

deeper. 

How do scientists count ocean animals? Specifi c equipment and strategies have 

been developed to better estimate various populations. One of these is the Alaskan Walleye pollock, a close relative of the cod fi sh. This species is an important 

source of food (fi sh sticks, cat food, imitation crab meat among many other 

items) and is the center of a multi-million dollar fi shery. One way scientists 

count pollock is by echolocation. They shoot sound waves through the water, 

and the waves bounce off the fi shes’ swim bladders (sacks fi lled with air inside 

the fi sh). The acoustic image the scientists see can include other fi sh, so the 

only way to be sure how many pollock are in a specifi c area is to bring the fi sh 

up using a sample trawl net. Once the pollock are caught in the net, they are all 

counted, right? Well, not really. It is very diffi cult to count that many fi sh. What 

researchers do instead is get a subsample, a smaller sample of the whole. First, 

they weigh the net of pollock, and then 

the fi sh are split into a few subsamples. 

Scientists fi nd the average age and 

weight of the pollock in each subsample. 

Then they estimate the total biomass for 

the entire net of fi sh, the sample. For example, if one fi sh weighs 3 pounds, then 

there must be 10,000 fi sh in a 30,000 

pound sample. Based on the main sample, the net full of fi sh, the grand total 

of fi sh in a school of pollock seen with 

echolocation can then be estimated.

But how do scientists know where they 

counted fi sh and where they did not? They put an imaginary grid over the ocean 

fl oor in a certain area, and then count the fi sh in diff erent squares of that grid; 

a method called surveying. You can do the same thing scientists do with your 

friends or your class with an activity called Fish Fetch. 

Fish Fetch Fish Fetch

What You Will Do

Perform a demonstation of a survey technique 

used by scientists to estimate fish populations.

Courtesy Alaska Fisheries Science Center, NOAA like it warm and sunny at the surface, but others like it cold and dark where it is 

researchers do instead is get a subsample, a smaller sample of the whole. First, 

they weigh the net of pollock, and then 

the fi sh are split into a few subsamples. 

Scientists fi nd the average age and 

weight of the pollock in each subsample. 

Then they estimate the total biomass for 

the entire net of fi sh, the sample. For example, if one fi sh weighs 3 pounds, then 

there must be 10,000 fi sh in a 30,000 

pound sample. Based on the main sample, the net full of fi sh, the grand total 

of fi sh in a school of pollock seen with 

echolocation can then be estimated.

Courtesy Alaska Fisheries Science Center, NOAA
National Oceanic and Atmospheric Administration (NOAA)

Science | Service | STEWARDSHIP

99

Protect the Earth

What You Will Need

r Blue tarp with a 10 x 10 grid of 1 square foot 

cells laid out with yellow duct tape

r 1000 Fish-shaped craft beads, approximately 

1” in length and in assorted solid colors, (to 

represent the total fish population)

r 5 plastic sand pails, referred to as “scientifically calibrated sample buckets”

r 5 sample selectors (e.g. soft foam boat, preferably one that bounces erratically rather 

than rolling)

r Whiteboard or flipchart to write on

r Whisk broom (optional) to redistribute fish 

after sampling

How to Do It

1. Scatter the 1000 fish around on the grid.

2. Ask, “How many fish do you think are on the 

grid?” (This is an initial guess – some will 

take a wild guess, others will try to figure it 

out visually in a more systematic way).

3. Players next go “out into the ocean” and throw 

their squishy boat onto the grid. The square 

that the ship lands on is the random sample.

4. Players count all the fish in the blue part of 

the square and put the fish into their bucket. 

5. Players record the number of fish in each 

sample on the whiteboard or flipchart. 

Counts of zero are valid observations.

6. Ask “How can you figure out, on average, 

how many fish were in the squares that you 

counted?” (Answer: add up the number of 

fish in the samples, and divide by the number 

of samples). Players can do the math themselves on the whiteboard, or an adult can do 

it for them.

7. Ask, “If this is the average number of fish per 

square, how can you figure out how many fish 

there are in all?” (Answer: count the number 

of squares in the grid—100—and multiply the 

average number by 100).

8. Compare the initial guess of how many fish 

there were to the estimate using the samples.

9. Throw the fish back into the “sea.” The whisk 

broom can be used to redistribute the fish 

around the grid. You can experiment with an 

even distribution of fish or a clumped distribution (where some squares have a lot of fish 

in them and others have none).

Want to Do More?

1. Check out NOAA Fisheries Service’s education 

resources:

Alaska Fisheries Science Center: www.afsc.

noaa.gov/Education/default.htm

Northwest Fisheries Science Center: www.

nwfsc.noaa.gov/education/index.cfm

Pacific Islands Fisheries Science Center: www.

pifsc.noaa.gov/outreach/

Northeast Fisheries Science Center: www.

nefsc.noaa.gov/#

Southeast Fisheries Science Center: www.

sefsc.noaa.gov/education/

Southwest Fisheries Science Center: swfsc.

noaa.gov/swfsc.aspx?id=7532&ParentMenuId=33

West Coast Region: www.westcoast.fisheries.

noaa.gov/education/index.html

Pacific Islands Region: www.fpir.noaa.gov/

PAO/pao_outreach_edu_index.html

Southeast Region: sero.nmfs.noaa.gov/outreach_education/index.html

Greater Atlantic Region: www.greateratlantic.

fisheries.noaa.gov/educational_resources/kids/index.html

2. Play games! games.noaa.gov/

https://www.aliexpress.com
noaa.gov

Discover Your World With NOAA

100

Does this look like a drugstore?

Some of our most widely-used drugs come from nature:

• Aspirin was first extracted from the willow tree

• Morphine is extracted from the opium poppy

• Penicillin was discovered in common bread mold

Historically, almost all of our drugs from natural sources came from 

plants and animals that live on land. But recent searches for new drugs 

have discovered that marine invertebrates (animals without backbones) 

produce more antibiotic, anti-cancer, and anti-inflammatory substances 

than any group of organisms on land. Strangely, many of these substances come from animals that spend most of their lives just sitting around. 

If you looked at these animals in an aquarium, you would probably get 

bored pretty quickly because they don’t move, and just look like blobs or 

skinny plants. And because they don’t look very interesting, you might 

assume that they are not important. 

What You Will Do

Make a poster to explain that we should protect animals that seem unimportant because they may 

provide new drugs for treating diseases such as heart disease, arthritis, and cancer

The Ocean Drugstore

But guess again! These unimpressive animals may hold the key to curing 

some of the most serious diseases that affect humans! Here’s a way that 

you can help teach other people not to jump to conclusions about the 

importance of ocean animals.

NOAA’s Office of Ocean Exploration and Research has supported several 

expeditions to search for new drugs from the sea. The 2003 Medicines 

from the Deep Sea expedition was the first scientific exploration of marine organisms from deep-water habitats in the Gulf of Mexico. Samples 

collected during the expedition are being studied by scientists at Harbor 

Branch Oceanographic Institution for chemicals that may lead to new 

ways to treat cancer, infectious diseases, disorders of the immune and 

central nervous systems, and cardiovascular disease.
National Oceanic and Atmospheric Administration (NOAA) 101

Science | Service | STEWARDSHIP PROTECT THE EARTH

What You Will Need

❒ Copies of images from “Some Animals That 

Produce Raw Materials for New Drugs”

❒ Crayons, colored markers, or colored pencils

❒ Poster board

❒ Scissors (Be careful with sharp scissors!)

How to Do It

1. Use images and information from the worksheet to create a poster that explains why it 

is important to protect seemingly uninteresting ocean animals using the fact that these 

animals may be sources of important new 

drugs for treating human diseases.

2. Show your poster at school, to your parents, 

and to other groups. The more people know 

about the importance of ocean life, the more 

they will support actions to protect ocean 

resources.

Want to Do More?

Visit oceanexplorer.noaa.gov/explorations/03bio/welcome.html for more about the 

Ocean Explorer Medicines from the Deep Sea 

Expedition and oceanexplorer.noaa.gov/facts/

medicinesfromsea.html for a fact sheet.

This activity was adapted from Chemists with no Backbones 

(4 pages, 356k) by Mel Goodwin, The Harmony Project, 

Charleston, SC; from the Ocean Explorer 2003 Medicines from 

the Deep Sea Expedition [oceanexplorer.noaa.gov/explorations/03bio/background/edu/media/meds_chemnobackbones.pdf]

Why Do Simple Animals Produce Powerful Drugs?

Many of ocean animals that produce powerful 

substances are sessile, which means that they 

do not move. This may give a clue about why 

they produce these substances: Basically, these 

animals are “sitting ducks,” so they may use 

powerful chemicals to repel predators. Another 

possibility is that since many of these species 

are fi lter feeders, they are exposed to all sorts 

of parasites and disease-causing bacteria in 

the water; so the powerful chemicals may be a 

defense against parasites or antibiotics against 

disease-causing organisms. Competition for 

space may explain why some of these animals 

produce anti-cancer substances: If two species 

are competing for the same piece of bottom 

space, it would be helpful to produce a substance 

that would attack rapidly dividing cells of the 

competing organism. Since cancer cells often 

divide more rapidly than normal cells, the same 

substance might have anti-cancer properties.

Competition for resources is intense in habitats such as reefs. Many of the sessile invertebrates produce 

natural products to help them be more competitive. Photo courtesy John Reed, NOAA.
noaa.gov

Discover Your World With NOAA

102

This is a colony of tunicates. 

Tunicates are animals whose 

body is basically a sack with 

two openings called siphons 

through which water enters 

and exits. Small particles 

fi ltered out of the water 

are used for food. They are 

called tunicates because their 

body wall resembles a coat 

or “tunic.” Some tunicates 

produce a chemical called 

Ecteinascidin, which is being 

tested in humans for treatment 

of breast and ovarian cancers 

and other solid tumors.

Sponges are the most primitive invertebrate animals that 

are composed of more than 

one cell. They do not have 

tissues or organs, but some 

of their cells are specialized 

to perform specifi c functions. 

Sponges of the genus Forcepia

produce substances called Lasonolides, which may provide 

new treatments for cancer. 

Other sponges belonging to 

the genera Topsentia, Hexadella, and Spongosorites produce 

a chemical named Topsentin, 

which is an anti-infl ammatory 

that may be helpful in treating diseases like arthritis. 

Deep-sea sponges of the genus 

Discodermia produce a tumor-fi ghting substance called 

Discodermalide.

Bryozoans are small, mosslike animals that do not move. 

They feed on very small fl oating animals called zooplankton. Some bryozoans produce 

a chemical called Bryostatin 

that may be useful in treating 

certain types of cancer such as 

leukemia and melanoma.

Some Animals That Produce Raw Materials for New Drugs

Photo courtesy NOAA. Photo courtesy NOAA. Photo courtesy NOAA. Courtesy Photo Collection of Dr. James P. McVey, 

NOAA Sea Grant Program

Photo courtesy NOAA. 

Gorgonians are a type of soft 

coral, also called “sea whips.” 

Pseudopterogorgia elisabethae 

is a sea whip that produces 

substances called Pseudopterosins (soo-doh-TER-ohsins) that reduce swelling and 

skin irritation and accelerate 

wound healing.

Cone snails (also called cone 

shells) are carnivorous marine 

snails found in coral reefs. In 

this picture, the cone snail 

Conus marmoreus is eating a 

cowrie (another kind of snail). 

Cone snails produce a venom that helps capture food. 

The venom of some species 

is powerful enough to kill a 

human being. The cone snail 

Conus magnus also produces a 

chemical named ω-conotoxin 

MVIIA , which is a powerful 

pain-killer.
National Oceanic and Atmospheric Administration (NOAA) 103

Science | Service | STEWARDSHIP PROTECT THE EARTH

Who Trashed the Ocean?

“During our 5,000-meter dive in Sirena Canyon, along the 

Mariana Trench wall, we saw multiple pieces of marine 

debris. A soda can, a food tin, and a piece of rope all 

accompanied the fish, corals, and rocks that we imaged 

as we moved up the slope. We encountered even more trash 

(nine pieces!) on our dive the following day, including several plastic bags and a piece of clothing. Even 

in one of the deepest places on Earth, humans have left 

their mark.”

~ from NOAA Ocean Explorer 2016 Deepwater Exploration of the Marianas

Mission Log Earth Day, April 22, 2016

Diva Amon, University of Hawaii at Manoa

Deborah Glickson, NOAA Cooperative Institute for Ocean Exploration, Research, and Technology

oceanexplorer.noaa.gov/okeanos/explorations/ex1605/logs/apr22/welcome.html

Marine debris is man-made trash that enters the ocean or Great Lakes 

environment. 

The world’s ocean is constantly polluted with a wide variety of trash ranging 

from soda cans and plastic bags to derelict fi shing gear and abandoned vessels. 

Every day, marine debris impacts marine animals and their habitats. Wildlife can 

become entangled in debris or eat pieces of plastic trash, and valuable habitats 

can be smothered or damaged. Humans are impacted, too. Divers, ships, and 

boats can also become entangled in debris and garbage that litters beaches and 

waterfronts not only looks awful—it also costs thousands of dollars to clean up.

The NOAA Marine Debris Program is the federal lead to investigate and prevent 

the negative impacts of marine debris. They do that by learning more about 

debris in order to best address it, reducing the amount of debris in the environment by cleaning it up, and most importantly, working to prevent marine debris 

in the fi rst place. We can prevent marine debris by educating people about its 

consequences and why we need to stop trashing the ocean.

And that’s where you come in!

What You Will Do

Make a poster to inform people 

about why marine debris is bad 

and why we need to stop it.

When exposed to light, plastics break down into small pieces through a process known as 

‘photodegradation.’ These small bits of plastic, known as microplastics, make up the majority of items found in the so-called ‘Pacifi c Garbage Patch,’ where they fl oat suspended in 

the water column. Image courtesy NOAA.

Who Trashed the Ocean?
noaa.gov

Discover Your World With NOAA

104

What You Will Need

r Crayons, colored markers, or colored pencils

r Poster board

r Scissors (Be careful with sharp scissors!)

r (Optional) Copies of images from “Some Examples of Marine Debris Posters”

r (Optional) Laptop computer, printer

How to Do It

1. Use the examples and your own ideas to create a poster that explains the consequences 

of marine debris, and what we can do to stop 

it.

2. Show your poster at school, to your parents, 

and to other groups. The more people know 

about marine debris and what it does, the 

more they will take personal action to prevent it.

Want to Do More?

1. Visit the NOAA Marine Debris Program Web 

site at marinedebris.noaa.gov/ for more 

about marine debris, as well as information, 

videos, photographs and more about cleanup 

and prevention projects.

2. Check out marinedebris.noaa.gov/resources

for more marine debris poster ideas.

If you have a desktop computer and printer, you can download images from the NOAA Marine Debris 

Program web site (marinedebris.noaa.gov/) and create your own poster with your own ideas.

Marine debris threatens marine life and our oceans and 

coasts. It affects us too, whether we are boating, fishing, 

swimming, or simply enjoying a day at the beach. Trash 

can travel through storm drains, streams, and rivers and 

end up in your community, as well as in the ocean. 

Learn ways to stop this from happening. 

State of Hawaii 
National Oceanic and Atmospheric Administration (NOAA) 105

Science | Service | STEWARDSHIP Protect the Earth

Here are some more facts you can use to create your poster 

also from NOAA’s Marine Debris web site.

This background photo, taken after a 21-day 

marine debris removal effort by the Pacific 

Island Fisheries Service Coral Reef Ecosystem 

Division, shows 4,781 bottle caps collected from 

Midway Atoll’s shoreline. Most plastic bottle 

caps are made from polypropylene, also known 

as plastic #5-- a hard, durable plastic that can 

be difficult to recycle in some municipalities.

IMPACTS

OF MARINE DEBRIS

!

WORLDWIDE,

MORE THAN

200

SPECIES

ARE IMPACTED BY

ENTANGLEMENT 

PACKING BANDS ARE 

RESPONSIBLE

FOR MORE THAN HALF OF THE 

STELLER

SEA LION 

ENTANGLEMENTS

IN ALASKA

AT LEAST

1/3 OF ALL

SEABIRD

SPECIES

EAT DEBRIS

ALL

SEA TURTLE

SPECIES

EAT DEBRIS

GET INVOLVED and participate in local 

cleanups in your area. 

REMEMBER that our land and sea are 

connected. 

DISPOSE OF WASTE PROPERLY

no matter where you are.

REDUCE the amount of waste you produce. 

REUSE items when you can. Choose reusable 

items over disposable ones.

RECYCLE as much as possible! Bottles, cans, 

cell phones, ink cartridges, and many other 

items can be recycled.

INGESTION 

Animals mistakenly eat plastic and other debris.

ENTANGLEMENT & GHOSTFISHING 

Marine life gets caught and killed in ghost nets, trapped 

in derelict gear, and entangled in plastic bands and other 

marine debris.

HAZARD TO NAVIGATION 

below the water’s surface. Encounters with large items at sea 

can result in costly vessel damage, either to its structure or 

through a tangled propeller or obstruct mechanical gears.

HABITAT DAMAGE 

Heavy marine debris crushes sensitive habitat, such as coral 

reefs and sea grass.

NON-NATIVE SPECIES 

Marine debris transports alien and invasive species from one 

region to another.

ECONOMIC COST 

Communities lose a lot of money cleaning up trash, as well as 

HOW

Y

CAN HELP

OU Facebook: 

www.facebook.com/

NOAAMarineDebris

Instagram & Twitter

@NOAADebris

Website

http://marinedebris.noaa.gov

DEBRIS

FACTS

$$$

GARBAGE 

PATCHES Currents and winds move marine debris 

throughout the ocean, sometimes far 

from its origin. “Garbage patches” are 

areas in the ocean where marine debris 

accumulates because of converging 

currents. These areas are not solid 

islands of trash that you can see easily 

with the naked eye. They are made 

up mostly of tiny microplastics swirling 

throughout the ocean’s water column. 

Garbage patches exist in ocean gyres 

all over the world. 

PLASTIC 

MARINE DEBRIS 

debris in the ocean. Globally, we are 

consuming more and more single-use 

plastic items, but many countries lack 

the waste infrastructure to process it. In 

places where there is good infrastructure, 

intentional littering or improper disposal 

may add to the problem. 

Plastic does not biodegrade in the ocean. 

It can fragment into tiny pieces called 

microplastics, less than 5 mm in length, 

from weathering and sun exposure. 

Plastics in the ocean can last for hundreds 
noaa.gov

Discover Your World With NOAA

106

It All Runs Downhill

What do you think of when you hear the word “pollution?” Black smoke belching out of factories? Horrible fl uids pouring out of huge pipes?

Thirty years ago, these were classic symbols of pollution. But a lot of progress 

has been made in reducing pollution from sources such as industrial facilities 

and sewage treatment plants. Today, the big water pollution problem comes 

from rainwater and melting snow. Rain and snow are usually pretty clean when 

they fall from the sky. But as water fl ows over and through the ground it picks 

up chemicals, oil, animal wastes, and many other contaminants that change 

clean water into polluted runo .

This kind of contamination comes from many sources, such as

• fertilizers and pest control chemicals from farms and home landscapes; 

• oil, grease, and toxic fl uids from roads, parking areas, and motor vehicles;

• acid drainage from abandoned mines; and 

• wastes from livestock, pets, and leaking septic tanks.

Because the contaminants cannot be traced to a single source, this kind 

of pollution is called “nonpoint source pollution” or polluted runo . More 

than half of the watersheds in the U.S. are a ected by nonpoint source 

pollution. A “watershed” is an area of land that catches precipitation and 

channels this water into a marsh, stream, river, lake, or underground reservoir 

(groundwater). Your can think of a watershed as a giant funnel. Water that falls 

on any land within the watershed will all be funneled to the same water body. 

Watersheds can be small, feeding to a single stream or pond. Several small 

watersheds may be part of a larger watershed that funnels into a larger stream 

or river, and eventually into the ocean.

The only way to stop nonpoint source pollution is through education about the 

problem and what people can do to prevent watershed contamination. Here’s a 

way that you can help!

What You Will Do

Make a model of a watershed, and show how 

rainfall carries pollution into the ocean 

and other water bodies.

Iron contamination in the Idaho Blackbird Creek, Lemhi County, Idaho. Courtesy NOAA

It All Runs Downhill
National Oceanic and Atmospheric Administration (NOAA) 107

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What You Will Need

r Rectangular container, about ten inches x 

twelve inches x two inches; a metal baking 

pan or plastic storage container is perfect

r Two sheets newspaper

r Plastic wrap or a white garbage bag

r Spray bottle

r Water

r Blue food coloring, about four drops

r Baby powder, cocoa powder, colored drink 

powder, and/or cake sprinkles; about two 

tablespoons

How to Do It

1. Crumple two sheets of newspaper, and place 

them side by side in one end of the container, 

like this:

2. Stretch the plastic wrap or garbage bag over 

the wads of newspaper and down over the 

sides of the container. Press the plastic down 

into the container in the end without the 

newspaper so that it forms a shallow depression. Be sure the plastic extends all the way 

over both sides of the container. The wads 

of newspaper represent hills or high places 

in your model watershed, and the shallow 

depression represents lakes, rivers, or the 

ocean.

3.

Sprinkle a little baby powder, drink powder, 

cocoa, or cake sprinkles on the hills of your 

model to represent pollution. You can use 

diff erent materials to represent diff erent 

types of pollution. For example, baby powder could represent fertilizer; cocoa powder 

might represent motor oil or vehicle exhaust; 

colored drink powder could represent chemical runoff ; and chocolate cake sprinkles 

could represent animal waste.

4. Predict where the pollution will fl ow and how 

many watersheds you think you have. Now, 

rapidly spray water onto the hills to show 

how rainfall carries pollution into the ocean 

and other water bodies. Were your predictions accurate?

5. You can use your model to teach other people 

about nonpoint source pollution. Be sure to 

talk about things that everyone can do to 

help solve this problem! Here are some ideas:

• Keep trash, pet waste, chemicals, etc. out 

of storm drains, since these often drain 

directly to lakes, streams, rivers, or wetlands

• Find out about alternatives to lawn and 

garden chemicals such as mild detergents, 

planting native species, and alternating 

rows of herbs with rows of vegetables to 

attract pest predators such damsel bugs, 

ladybugs, and stingless wasps

• Learn how to properly dispose of used oil 

and hazardous household chemicals

• Dispose of pet wastes in the garbage or 

toilet

 You can fi nd more ideas at www.epa.gov/

hwp and www.epa.gov/hwp/basic-information-and-answers-frequent-questions

Want to Do More?

1. See NOAA’s National Ocean Service Nonpoint 

Source Pollution Tutorial: oceanservice.

noaa.gov/education/kits/pollution/04nonpointsource.html to fi nd out more about nonpoint source pollution

2. See EarthLabs for instruction on how to make 

a more realistic model of a watershed: serc.

carleton.edu/eslabs/drought/2a.html

3. Visit help.waterdata.usgs.gov/tutorials/

site-information/ and click on “What is my 

watershed address and how will it help me 

fi nd USGS data? (or What is a Hydrologic 

Unit?)” to fi nd your watershed address.

Newspaper

Plastic wrap
noaa.gov

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108

Toxic! Or Is It?

One of the big questions about any type of pollution is, “Will it hurt plants, 

animals, or humans?”

How can we fi nd out? We don’t want to risk harming lots of living organisms to 

see whether a substance is toxic, especially if the organisms are humans! 

Scientists investigating pollution often use a technique called “bioassay” to 

test for toxicity. A bioassay is a measurement of the eff ects of a substance on 

living organisms. Tests for toxic substances use certain species called “indicator species,” which may be juvenile fi shes, plant seeds, microscopic animals, 

or even bacteria! Several individuals of an indicator species are exposed to 

the substance being tested for a certain period of time, and then compared 

to another group of the same species that was not exposed to the substance 

(the second group is called the “control group”). If the organisms in the test 

group show eff ects such as slow growth, reduced movement, or death and these 

eff ects are not seen in the control group, this is considered to be an indication 

that the substance being tested is toxic.

Bioassays usually do not indicate which specifi c substances cause toxicity, or 

the amounts of toxic substances present. But they do provide a good indication 

of the total toxicity of samples that may contain more than one toxic substance, 

and they are a quick and inexpensive way to test for toxicity in many samples.

Here is a simple bioassay that you can use to test for toxicity in runoff water 

that you suspect may be contaminated.

What You Will Do Use a radish seed bioassay to test for toxicity

Beach pollution at Bay St. Louis, MS after Hurricane Katrina. Courtesy NOAA.

What You Will Need

❒ 12 or more ziplock plastic bags

❒ One paper towel for each plastic bag

❒ Ten radish seeds for each plastic bag

❒ Permanent marker for labeling sample jars and plastic bags

❒ Household bleach, about 1/4-cup

❒ Distilled water, about one quart

❒ Ruler graduated in millimeters (mm)

❒ Tweezers or forceps

❒ Glass containers for collecting samples; baby food jars or similar size are 

perfect

❒ Clean glass jar for mixing bleach solution, about one pint

❒ Measuring cup that is not used for food

❒ Protective gloves and safety glasses, one set for each person participating 

in this activity

Beach pollution at Bay St. Louis, MS after Hurricane Katrina. Courtesy NOAA.
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Warnings

 Do this activity with an adult partner!

 Always check with an adult before collecting 

samples that may be contaminated with 

harmful substances. 

 Wear protective gloves and safety glasses when 

handling sample solutions!

 Do not use glasses, dishes, or any container that 

is used for food!

 Wash your hands after handling sample solutions, paper towels, and seeds!

How to Do It

1. Collect water samples to be tested. You may 

want to test water from puddles, streams, or 

ponds. Do this ONLY with an adult partner! 

Wear protective gloves and safety glasses! 

Collect each sample in a clean glass jar, and 

label the jar with a number.

2. Put on protective gloves and safety glasses, 

then mix one ounce of household bleach with 

nine ounces of distilled water in a clean glass 

jar.

3. Put the radish seeds in a clean glass container, and add about two ounces of the bleach 

solution from Step 2. The bleach solution 

kills fungi, which could interfere with seed 

germination.

4. Bioassays are carried out in zip-lock plastic 

bags containing a paper towel saturated with 

the test solution. Saturated means that the 

towel is damp all over, but isn’t dripping. 

Three separate tests (called “replicates”) 

will be done for each solution. Prepare three 

plastic bags for each sample to be tested, 

plus three more bags for the control solution (distilled water). Label each bag with 

the sample number, plus a letter to identify 

the three replicates (so for sample number 

1, there would be three bags labeled “1-A,” 

“1-B,” and “1-C”). Put a folded paper towel in 

each bag.

5. Pour enough sample solution into each bag 

to saturate the filter paper. Use the same 

amount of sample in all tests. Saturate the 

paper towels in the control bags with the 

same amount of distilled water.

6. Using tweezers or forceps, place ten seeds on 

the paper, evenly spaced, in each bag. Seal 

the top of the bag.

7. Put the bags on a tray or shallow box where 

they can remain for five days. The bags 

should be at room temperature, but do not 

place them in direct sunlight! Each day, 

record the number of seeds that germinated 

(split open) in each bag, and measure (to the 

nearest mm) the length of the root that has 

emerged from each germinated seed. 

8. At the end of five days, calculate the average 

number of seeds that germinated in the three 

bags for each sample and for the controls. 

Also, calculate the average length of the 

roots among the germinated seeds in the 

three bags. If fewer seeds germinated in bags 

containing test samples, or if the roots grew 

more slowly than in the control bags, this is 

an indication that the samples may contain 

toxic substances.

Want to Do More?

1. For more information about simple bioassays, 

see

www.wwoa.org/resources/public-education/

lettuce-seed-bioassay/

2. Visit www.epa.gov/nutrientpollution for more 

information about polluted runoff.

3. Visit oceanservice.noaa.gov/education/lessons/the_seeds.html for a lesson on nonpoint source pollution called The Seeds Tell 

the Story.
noaa.gov

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110

In the late 1860’s, it seemed like a good idea: Let’s 

start a silk industry in the United States! Silk is a valuable cloth, in demand all over the world. And insects 

do most of the work! All we need to do is import some 

Gypsy moths from France, then sit back and wait for 

the money to start rolling in!

So, the moths were imported. Unfortunately, they 

escaped. Today, Gypsy moths are a major threat to U.S. 

forests. 

Gypsy moths are one example of invasive species, and 

there are many more. About 50,000 alien species 

are already in the U.S. What’s the diff erence between 

“alien” and “invasive?” An alien species is not native 

to a particular ecosystem. If an alien species causes 

economic and/or environmental harm or threatens 

human health, then it is called invasive.

What’s the big deal? Invasive species can seriously threaten native species and 

entire ecosystems. Plus, the costs of environmental damage, economic losses, and 

eff orts to control invasive species average $138 billion per year—more than the cost 

of all other natural disasters combined. 

What can be done? NOAA’s National Centers for Coastal Ocean Science are developing a group of experts that can help recognize alien species, hopefully before 

they become invasive. NOAA’s National Sea Grant Offi ce and state fi sh and wildlife 

agencies are partnering with the pet industry in the HabitattitudeTM Campaign, 

which is about educating consumers about possible environmental consequences of 

aquarium and water garden hobbies, and how to be a responsible hobbyist. In addition, NOAA’s Community-Based Restoration Program works with community groups 

to remove invasive plants as part of projects to repair damaged coastal habitats.

Here’s how to learn a lot about aquatic invaders and have fun at the same time!

Invasive Species Super Sleuth

Lionfi sh are venomous fi sh from Indian and western Pacifi c oceans 

that have invaded East Coast waters Courtesy NOAA.

What You Will Need

Access to the internet.

How to Do It

Play Nab the Aquatic Invader and Be a Sea Grant 

Super Sleuth at www.iiseagrant.org/NabInvader/.

Want to Do More?

1. You can fi nd a LOT more information on invasive species on the Nab the quatic Invaders! Be a 

Sea Grant Super Sleuth website (www.iiseagrant.

org/NabInvader/). Click on “Information for 

Teachers” to go to all kinds of good links.

 2. Visit the GloBallast web site archive.iwlearn.

net/globallast.imo.org/globallast.imo.org/index.html and watch 

Invaders from the Sea a very informative IMO-BBC documentary about the 

transfer of harmful organisms in ballast water from ships. You can also 

fi nd it on youtube: www.youtube.com/watch?v=u5JkRtMTEdI.

3. Visit oceanservice.noaa.gov/facts/invasive.html and www.noaa.gov/

topic-tags/invasive-species and http://www.habitat.noaa.gov/pdf/

best_management_practices/fact_sheets/ and click on “Aquatic 

Imvasive Species Overview.pdf” for even more information!

What You Will Do

Play a game called “Nab the Aquatic Invader!” 

You will be a private investigator working with other detectives 

to catch suspected invaders including 

Louie “Sucker Mouth” Sea Lamprey, Zeke “The Prowler” Zebra Mussel, 

Purple “Lucky” Loosestrife, and Rocco “Ravenous” Ruffe.
National Oceanic and Atmospheric Administration (NOAA) 111

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If you have played the “Invasive Species Super Sleuth” game, you already know 

what invasive species are and why they are a big problem (so you can skip the 

rest of this paragraph!). Just in case you haven’t played the game yet, invasive 

species are plants, animals, or other living organisms that are not native to a 

particular ecosystem and cause economic harm, environmental damage, or 

pose a threat to human health. Invasive species can seriously damage native 

species and entire ecosystems, and cost an about $138 billion per year (which 

is more than the cost of all other natural disasters combined). NOAA’s National 

Centers for Coastal Ocean Science are developing a group of experts that can 

help recognize alien species, hopefully before they become invasive. NOAA’s 

National Sea Grant Offi ce and state fi sh and wildlife agencies are partnering 

with the pet industry in the HabitattitudeTM Campaign (www.habitattitude.

net/), which is about educating consumers about possible environmental 

consequences of aquarium and water garden hobbies, and how to be a responsible hobbyist. In addition, NOAA’s Community-Based Restoration Program works 

with community groups to remove invasive plants as part of projects to repair 

damaged coastal habitats.

You can help! Here are some pictures and more information about twelve invasive alien animals. You can use these images to make a twelve-sided object that 

will show these examples of invasive species. This twelve-sided object is called 

a dodecahedron (pronounced “doe - dek - ah - HEE - dron”). You can use your 

“Alien Dodecahedron” to help other people understand more about the invasive 

species problem. Once they start looking at the dodecahedron and the images 

on its twelve sides, you can tell them some of the facts about invasive species. 

Remember: Education and understanding are key to solving most environmental 

problems—including invasive species! 

What You Will Do

Make a dodecahedron that shows pictures of 

twelve invasive animals

Your Alien Dodecahedron

Courtesy USGS

Courtesy Leo G. Nico, USGS

Courtesy Justin Secrist, Washington DFW

Courtesy California Interagency Ecological Program
noaa.gov

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112

What You Will Need

❒ Color copy of images on the “Alien Dodecahedron Worksheet”

❒ Copy of “How to Fold a Dodecahedron” worksheet

❒ Scissors

❒ Glue for paper

Warning

Be careful with scissors; they are sharp!

How to Do It

1. Carefully cut out the pattern on the “How to 

Fold a Dodecahedron” worksheet. Be sure NOT 

to cut the dashed lines!

2. Fold all of the dashed lines away from you 

(backward), then unfold and fl atten the 

pattern.

3. Cut out the twelve images on the color copy of 

the “Alien Dodecahedron Worksheet.”

4. Glue the images onto the dodecahedron pattern. 

5. Fold the dodecahedron pattern along the 

dashed lines so that it makes a twelve-sided 

shape. Glue the tabs to keep the shape from 

unfolding. 

6. Now you have an Alien Dodecahedron! 

Look over the facts about each species on the worksheet. You will see that some alien invaders were 

deliberately brought to the United States for various reasons. Others arrived by accident, sometimes 

as part of “ballast water.” Ballast water is water 

that is pumped into large ships when they are not 

carrying cargo, so that they are more stable when 

sailing on the ocean. This means that water from 

one part of the Earth can be carried thousands of 

miles away before it is pumped out again. If small 

animals or larvae happen to be in the water when 

it is pumped into a ship, they get a free ride to 

another part of the world! 

You will also see that one of the biggest problems 

with invasive species is that they compete with native species. Native species are the organisms that 

are normally found in a certain ecosystem. Often, 

native species do not have good defenses against 

invaders. Species like the zebra mussel cause other 

problems when they attach themselves inside pipes 

that carry water in and out of factories or power 

plants. Some invaders are dangerous to humans, 

such as the lionfi sh that has spines that contain a 

powerful venom.

Show your Dodecahedron to other people and tell 

them about the invasive species problem. You can 

also play a game with your Dodecahedron: Players 

take turns, and the player who is “It” gently tosses 

the Dodecahedron onto a fl at surface, then looks 

at the picture that is face down. Time the player to 

see how long it takes to correctly name the species 

and what damage it causes (or whatever other 

facts you want to include in the game). If the facedown image has already been named by another 

player, the player who is “It” tosses the Dodecahedron again until a new image is face-down.

Want to Do More?

See www.habitat.noaa.gov/restoration/programs/invasivespecies.html and coastalscience.

noaa.gov/research/pollution/invasive/ to fi nd 

out more about invasive species and what is being 

done about them.

The National Invasive Species Information Center 

Web site, www.invasivespeciesinfo.gov/index.

shtml has a lot of information about invasive species, including links to images.

Lionfi sh, Courtesy Paula Whitfi eld, NOAA
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How to Fold a 

Dodecahedron 

Worksheet
noaa.gov

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114

Courtesy NOAA Restoration Center, Jim Turek

What Is It? 

A fish called an Alewife (also called mulhaden, 

grey herring, golden shad); its scientific name is 

Alosa pseudoharengus 

Where Did It Come From? 

Atlantic Ocean

How Did It Get Here? 

Deliberately introduced to Lake Erie

What Does It Do? 

Competes with native species

Courtesy Leo G. Nico, USGS, Gainesville, FL

What Is It? 

A fish called an Asian swamp eel or rice eel; its 

scientific name is Monopterus albus

Where Did It Come From? 

Asia

How Did It Get Here? 

Brought to the U.S. for aquariums and fish markets, accidentally released

What Does It Do? 

Competes with native species

Courtesy of California Interagency Ecological Program

What Is It? 

A crab called the Chinese mitten crab; its scientific 

name is Eriocheir sinensis

Where Did It Come From? 

China

How Did It Get Here? 

In ballast water of ships; possibly deliberately 

released

What Does It Do? 

Competes with native species

Alien Dodecahedron Worksheet

Alewife Asian Swamp Eel Chinese Mitten Crab
National Oceanic and Atmospheric Administration (NOAA) 115

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Courtesy Paula Whitfield, NOAA Center for Coastal Fisheries and 

Habitat Research, Beaufort, NC

What Is It? 

A fish called the lionfish; its scientific name is 

Pterois volitans

Where Did It Come From? 

Pacific Ocean

How Did It Get Here? 

Brought to the U.S. for aquariums; accidentally or 

deliberately released

What Does It Do? 

Eats native species and has venomous spines that 

are poisonous to humans

Courtesy U.S. Geological Survey, Florida Integrated Science Center]

What Is It? 

A fish called the Northern snakehead; its scientific 

name is Channa argus

Where Did It Come From? 

Asia

How Did It Get Here? 

Brought to the U.S. for fish markets; accidentally or 

deliberately released

What Does It Do? 

Feeds aggressively on amphibians, fish, birds, and 

small mammals; can survive in waters that contain 

very little oxygen and can travel across land

Courtesy Justin Secrist, Washington Department of Fish and 

Wildlife

What Is It? 

A mammal called a Nutria (also called a coypu, 

coypu rat, nutria rat, or swamp beaver); its scientific name is Myocastor coypus 

Where Did It Come From? 

South America

How Did It Get Here? 

Brought to the U.S. for fur production

What Does It Do? 

Damages vegetation and destroys wetland habitats

Lionfish Northern Snakehead Nutria
noaa.gov

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116

Courtesy D. Jude, University of Michigan

What Is It? 

A fish called the Round Goby; its scientific name is 

Neogobius melanostomus

Where Did It Come From? 

Eurasia

How Did It Get Here? 

In ballast water of ships

What Does It Do? 

Feeds on native species

Mouth of a sea lamprey

Courtesy USGS, Great Lakes Science Center

What Is It? 

A fish called a Sea Lamprey; its scientific name is 

Petromyzon marinus

Where Did It Come From? 

Atlantic Ocean

How Did It Get Here? 

Entered the Great Lakes through man-made canals

What Does It Do? 

Feeds on native species

Courtesy Dann Blackwood, U.S. Geological Survey

What Is It? 

An invertebrate called a Sea Squirt (also called 

an ascidian, colonial tunicate, or compound sea 

squirt]; its scientific name is Didemnum lahillei

Where Did It Come From? 

Europe

How Did It Get Here? 

In ballast water and attached to the hulls of ships

What Does It Do? 

Forms dense mats that smother native species

Round Goby Sea Lamprey Sea Squirt
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Courtesy of Ohio Sea Grant College Program

What Is It? 

A mussel called the Zebra Mussel; its scientific 

name is Dreissena polymorpha

Where Did It Come From? 

Eurasia

How Did It Get Here? 

In ballast water of ships

What Does It Do? 

Competes with native species, and clogs pipes of 

factories located on rivers and lakes

Courtesy of Julia Harding, Virginia Institute of Marine Science

What Is It? 

A snail called the Veined Rapa Whelk; its scientific 

name is Rapana venosa

Where Did It Come From? 

Pacific Ocean

How Did It Get Here? 

In ballast water of ships

What Does It Do? 

Eats commercially important bivalves, such as 

clams and oysters

Courtesy of California Interagency Ecological Program

What Is It? 

A crab named the European Green Crab; its scientific name is Carcinus maenas

Where Did It Come From? 

Europe

How Did It Get Here?

 In ballast water of ships

What Does It Do?

 Eats commercially important bivalves, such as soft 

shell clams and scallops

Zebra Mussel Veined Rapa Whelk European Green Crab
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118

“For most of the wild things on Earth, the future must 

depend upon the conscience of mankind”

~ Dr. Archie Carr, father of modern marine turtle biology and conservation

Earth loses hundreds of species every year, and many of these losses are 

the result of human activity. Some of these species may have held the 

key to curing cancer, or feeding everyone on the planet, or improving our 

lives in ways we can’t even imagine. But we’ll never know, because they 

are gone.

Congress passed the Endangered Species Act (ESA) on December 28, 

1973, recognizing that the natural heritage of the United States was 

of “esthetic, ecological, educational, recreational, and scientifi c value 

to our Nation and its people.” It was understood that, without protection, many of our nation’s living resources would become extinct.

Protecting endangered species needs everyone’s help, and the fi rst step is 

getting people to recognize the problem.

What You Will Do 

Make origami models of whales and turtles 

Here’s an activity that can help introduce the topic of endangered species, particularly whales and sea turtles.

What You Will Need

❒ 8 1/2 x 11 inches sheets of colored paper (one for each animal)

❒ Scissors

Warning

Be careful with sharp scissors.

Humpback whales in the singing position. Courtesy Dr. Louis M. Herman, NOAA

Endangered SpeciesOrigami
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1. Begin by making a square 

piece of paper. Fold one corner of a piece of paper over 

to the adjacent side.

2. Like this. Finish making the 

square by cutting off the 

small rectangle.

3. Fold side to side and unfold. 

This is the “valley fold” or 

“river.”

4. Turn over and fold right and 

left points down to form a 

“roof.”

5. Like this. Then turn over.

How to Make an Origami Sea Turtle

6. Bring the folded edges to 

meet the valley fold (the 

river). Crease flat.

7. Unfold the top side points.

8. Like this.

9. Fold the top point down as 

shown.

10. Fold the point upward to 

create a head.

11. Lift the bottom edge to meet 

the vertical center line.

12. Like this. Press flat and fold 

outward as shown.

13. Repeat steps 11 and 12 with 

the other foot.

14. Turn over. You’ve made a 

turtle!

Origami illustrations courtesy Matt McIntosh, NOAA
noaa.gov

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120

1. Begin by making a square 

piece of paper. Fold one corner of a piece of paper over 

to the adjacent side.

2. Like this. Finish making the 

square by cutting off the 

small rectangle.

3. Put a square of paper on the 

table so it looks like a diamond. Fold side to side and 

unfold.

4. Fold the lower left and right 

sides to meet the center 

crease.

5. It looks like an ice-cream 

cone. Now fold the top point 

down, as shown.

6. Fold the right side over to 

meet the left side.

7. Put your finger on the bottom 

point as you turn the whale 

sideways.

8. Fold the end point up to make 

a tail.

9. Like this.

10. Make a short cut through 

the end of the fold in the 

tail. Fold the edges of the 

tail outwards. 

11. Like this.

12. Draw eyes, fins and any 

other patterns you like.

Origami illustrations courtesy Matt McIntosh, NOAA

How to Make an Origami Blue Whale
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p Sea turtles have been on the planet since 

the early Mesozoic era almost 180 million 

years ago! They survived the great dinosaur 

extinction during the Cretaceous era, and 

fl ourished until recent times.

p There are six species of sea turtles commonly 

found in the United States in the Atlantic, 

Gulf of Mexico, and Pacifi c: 

4 Leatherback

4 Loggerhead

4 Kemp’s Ridley

4 Hawksbill 

4 Green

 4 Olive Ridley 

p Sea turtles eat a variety of organisms, including algae, seagrasses, sponges, crustaceans, 

jellyfi sh and mollusks. 

p Adult green turtles are unique among sea 

turtles in that they eat only plants; they are 

herbivorous, feeding primarily on seagrasses 

and algae. This diet is thought to give them 

greenish-colored fat, from which they take 

their name.

p Sea turtles have a unique life history. They 

are highly migratory, often swim long distances, live long lives, take a long time to 

reach maturity, and the females crawl ashore 

to dig nests and lay eggs.

p What’s the problem? Sea turtles are 

threatened by:

4 Loss of habitat and nesting areas due to 

coastal development

4 Incidental capture (bycatch) in commercial 

and recreational fi sheries

4 Being caught in or eating marine debris 

4 Being hit by ships

p NOAA and the U.S. Fish and Wildlife Service 

are working together to conserve and help 

marine turtles recover, along with other 

federal agencies, state partners, coastal 

communities, private individuals, and other 

nations.

p Some things being done to conserve sea 

turtles:

4 Requiring certain types of fi shing vessels to 

use fi shing gear that prevents accidental 

capture of sea turtles

4 Protecting and restoring prime nesting 

habitat along key coastal areas

4 Reduce entanglement in and ingestion of 

marine debris by sea turtles

4 Ensure coastal construction activities avoid 

nesting and hatching periods 

4 Supporting regulations to control artifi -

cial lights near turtle nesting beaches 

(artifi cial lights can disorient sea turtle 

hatchlings)

4 Working with other countries to conserve 

sea turtles throughout their range

p What can you do to help? 

4 Avoid sea turtles when you go out in a 

boat.

4 Do not anchor your boat in seagrass beds 

where sea turtles rest and eat.

4 Properly dispose of your garbage no matter where you live. It all fl ows downstream to the ocean.

4 Minimize all your lights at the beach 

(campfi res, fl ash lights, house lighting).

4 Celebrate events without balloon releases.

Learn as much as you can about sea turtles, the 

threats to the them, and their conservation. 

Share your knowledge with friends and family.

For more about sea turtle biology, status and the 

threats that face them, visit the U.S. Fish and 

Wildlife Service Web site: www.fws.gov/northfl orida/SeaTurtles/20090700_You_Can_Help_

ST.pdf. 

Sea Turtle Facts

Green Turtle Hawksbill Turtle

Caroline Rogers, USGS

Caroline Rogers, USGS
noaa.gov

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p Whales are 

the largest 

animals that 

ever lived on 

the Earth. They are even larger than the 

dinosaurs of prehistoric times. 

p All whales belong to a group known as cetaceans (seh TAY shuhnz). There are two types 

of whales—toothed (odontocete) and baleen 

(mysticete). Baleen is a special fi lter that 

whales use to sieve tiny food particles from 

the water.

p Today, there are 78 species of whales swimming in the oceans around the world; 67 

species are toothed and 11 are baleen.

p Whales are large, intelligent, marine mammals. They breathe air through a blowhole 

into lungs, are warm-blooded, and give birth 

to their young as opposed to laying eggs. 

p Many ceteaceans, especially baleen whales, 

migrate over very long distances each year. 

They travel, sometimes in groups (pods), 

from coldwater feeding grounds to warm-water breeding grounds. Gray whales make the 

longest seasonal migration of any of the 

whales—about 12,500 miles each year!

p The biggest whale is the blue whale, which 

grows to be about 94 feet (29 m) long —the 

height of a 9-story building. These enormous 

animals eat about 4 tons of krill (microscopic fl oating animals) each day, obtained by 

fi lter-feeding through baleen. 

p The smallest whale is the dwarf sperm whale, 

which as an adult is only 8.5 feet (2.6 m) 

long. 

p Adult blue whales have no predators except 

man. Almost all species of baleen whales 

were exploited by the commercial whaling 

industry from the 1700s to the mid-1900s. 

Several species of both toothed and baleen 

whales were hunted close to extinction. Most 

populations have not yet recovered from 

intense hunting and still face threats to their 

survival from human activities.

p Many baleen whales are in danger of being hit 

by ships, particularly the critically endangered Northern right whale. 

p Being tangled in various types of fi shing 

gear is a serious threat to several species of 

cetaceans.

p NOAA works 

to protect and 

conserve whales 

because all whales 

are protected under the Marine Mammal Protection Act, and 

some are also protected under the Endangered Species Act. 

p NOAA’s eff orts to protect and conserve whales 

include legislation, National Marine Sanctuaries and other marine protected areas. 

NOAA also works with the U.S. Fish and Wildlife Service on issues concerning whales and 

other ceteaceans. 

Want to Do More?

For more information, visit: 

NOAA’s Marine Mammals Program:

www.nmfs.noaa.gov/pr/species/mammals/

NOAA’s National Marine Sanctuaries: 

sanctuaries.noaa.gov/ – 

NOS’ What is a Marine Protected Area? oceanservice.noaa.gov/facts/mpa.html

U.S. Fish and Wildlife Service: www.fws.gov/

refuges/whm/coastalandmarine.html

Whale Facts

p p

to protect and 

conserve whales 

because all whales Humpback whale breaching Killer whale shyhopping

Courtesy NOAA Courtesy NOAA
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What You Will Do

Make a poster to explain how climate change is affecting polar ice mass, 

how it may affect humans, and what we can do about it. Courtesy Kathy Crane, NOAA Arctic Research Office

During the past thirty years, the Arctic environment has changed like 

never before. Temperatures have increased more than twice as much as 

on the rest of Earth and sea ice has been getting smaller and smaller. 

These changes have opened the Arctic to new commercial activities such 

as shipping, oil and mineral exploration and tourism. These new opportunities have increased the need to understand more about Arctic change 

and its effects on weather and climate, as well as how it may affect human 

communities and industry. The information that NOAA generates about the 

Arctic helps to conserve and manage Arctic resources to provide healthy, 

productive and resilient communities and ecosystems.

The Arctic Report Card for 2016 is a report that brings together the work of 

61 scientists from 11 nations who report on air, ocean, land and ecosystem 

changes. It is used around the world to track changes in the Arctic and how 

those changes may affect communities, businesses and people.

What are the 

Impacts of 

shrinking 

Polar Ice Caps?

“Rarely have we seen the Arctic show a clearer, 

stronger or more pronounced signal of persistent 

warming and its cascading effects on the 

environment than this year.”

~ Jeremy Mathis, director of NOAA’s Arctic Research Program

What are the 

Impacts Of

Shrinking 

Polar Ice caps?
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Major findings in the 2016 report include:

• Warmer air temperature: Average annual air 

temperature over land areas was the highest 

in the observational record, representing a 6.3 

degree Fahrenheit (3.5 degree Celsius) increase 

since 1900. Arctic temperatures continue to 

increase at double the rate of the global temperature increase.

• Record low snow cover: Spring snow cover set 

a record low in the North American Arctic, 

where the May snow cover extent fell below 

1.5 million square miles (4 million square 

kilometers) for the first time since satellite 

observations began in 1967.

• Smaller Greenland ice sheet: The Greenland ice 

sheet continued to lose mass in 2016, as it 

has since 2002 when satellite-based measurement began. 

• Record low sea ice: The Arctic sea ice minimum 

extent from mid-October 2016 to late November 2016 was the lowest since the satellite 

record began in 1979. Arctic ice is thinning, 

with multi-year ice now comprising 22 percent 

of the ice cover as compared to 45 percent of 

ice cover in 1985.

• Above-average Arctic Ocean temperature: Sea 

surface temperature in August 2016 was 9 

degrees Fahrenheit (5 degrees Celsius) above 

the average for 1982-2010 in the Barents and 

Chukchi seas and off the east and west coasts 

of Greenland.

• Arctic Ocean productivity: Springtime melting 

and retreating sea ice allowed for more sunlight to reach the upper layers of the ocean, 

stimulating widespread blooms of algae and 

other tiny marine plants which form the base 

of the marine food chain, another sign of the 

rapid changes occurring in a warming Arctic.

The 2016 report also includes scientific essays 

on carbon dioxide in the Arctic Ocean, on land 

and in the atmosphere, and changes among 

small mammals.

• Ocean acidification: More than other oceanic 

areas, the Arctic Ocean is more vulnerable to 

ocean acidification, a process driven by the 

ocean’s uptake of increased carbon dioxide 

from Earth’s atmosphere. Ocean acidification is 

expected to intensify in the Arctic, adding new 

stress to marine fisheries, particularly those 

that need calcium carbonate to build shells. 

This change affects Arctic communities that 

depend on fish for food security, livelihoods 

and culture.

• Carbon cycle changing: Overall, the warming 

tundra is now releasing more carbon into the 

(map) Temperatures across the Arctic from October 2015-September 2016 compared to the 1981-2010 average. (graph) Yearly temperatures since 1900 compared to the 1981-2010 average for the 

Arctic (orange line) and the globe (gray). NOAA Climate.gov map 

based on National Centers for Environmental Prediction (NCEP) 

reanalysis data from NOAA’s Earth System Research Lab. Graph 

adapted from Figure 1.1 in the 2016 Arctic Report Card. 
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atmosphere than it is taking up. 

Twice as much organic carbon is 

locked in the northern permafrost 

as is currently in the Earth’s atmosphere. If the permafrost melts and 

releases that carbon, it could have 

profound effects on weather and 

climate in the Arctic and the rest of 

the Earth.

• Small mammals: Recent shifts in 

the population of small mammals, 

such as shrews, may be the signs of 

broader consequences of environmental change.

These changes spell big trouble for animals that 

depend on sea ice for their survival. Polar bears, 

for example, live on sea ice all year. They rear 

their young on the ice, and hunt along the edges 

where seals make holes in the ice to breathe. 

An adult polar bear usually eats one seal every 

four or fi ve days. When the sea ice melts during 

the summer, polar bears have to swim between 

fl oating chunks of ice (called “fl oes”) to continue 

their hunt. Until recently, the fl oes were usually 

less than 15 miles apart. But as more and more 

of the perennial ice melts, the fl oes have become 

much farther apart, and the bears have had to 

swim over much longer distances. 

Polar bears face other problems, too. Ocean 

currents can carry chemical pollution thousands of 

miles, and some of it reaches the Arctic. Chemicals 

called PCBs, for example, have been found in polar 

bears. These chemicals cause problems with polar 

bears’ immune systems, so the bears are more 

likely to get sick. 

What You Will Need

❒ Color copies of images from “Images for 

Shrinking Polar Ice Caps” or other images 

you fi nd in web searches

❒ Information from the introduction to this 

activity.

❒ Crayons, colored markers, or colored pencils

❒ Poster board

❒ Scissors

Warning

Be careful with sharp scissors!

How to Do It

1. Use the images and information to create a poster that explains what is happening to arctic sea ice, how this is related to 

climate change, why this is important to 

us, and what we can do about it. 

2. Show your poster at school, to your parents, and to other groups. The more people 

know about climate change and how it affects life on Earth, the more they will take 

action to protect Earth’s ecosystems.

Want to Do More?

Take a look at the short video of Arctic Report Card 2016. www.youtube.com/

watch?v=G0rp6-BEur8&feature=youtu.be

For an in-depth read, go to the Arctic Report 

Card: Update for 2016 www.arctic.noaa.gov/

Report-Card/Report-Card-2016

www.arctic.noaa.gov/ – NOAA’s Arctic Theme 

Page with information and data about the 

Arctic for scientists, students, teachers and 

the general public.

For more information on methane, see www.

climate.gov/print/827815

For more information on ocean acidifi cation, see 

http://oceanacidifi cation.noaa.gov

The Greenland ice sheet continued to lose mass in 2016, as it has 

since 2002 when satellite-based measurement began. Melting began 

the second earliest in the 37-year record of observations, close to 

the record set in 2012. Graphic shows Greenland ice sheet mass 

each month since April 2002. (Climate.gov; data provided by Marco 

Tedesco/Lamont-Doherty)
noaa.gov

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126

Images for Shrinking Ice Cap Posters

Courtesy NASA

Courtesy NASA

(map) Stretching from Alaska to Scandinavia to Russia, and hundreds of feet deep in places, the Arctic’s frozen soils--permafrost--contain twice as much carbon as what’s already in the atmosphere. As the Arctic heats up, permafrost may become a major source of greenhouse gases, which would further accelerate global warming. (top middle) Permafrost is like a giant freezer for carbon: thousands of years worth of plant, animal, and microbe remains mixed with blocks of ice. Historically, only a shallow “active layer” thawed in the short summer. (top right) In today’s warming Arctic, permafrost is thawing and the active layer is getting deeper. (bottom left) Warming in the growing season has increased plant growth and allowed plants to remove more carbon dioxide (CO2) from the air during photosynthesis, but it is also thawing the frozen soils and stimulating decomposition of organic matter by soil microbes. Microbial activity releases the greenhouse gases CO2 and methane (CH4). (bottom right) When winter comes, the uppermost soil layer re-freezes quickly as air temperatures drop. But deeper layers, insulated from the frigid air, re-freeze more slowly. In the past decade, the parts of the Arctic tundra that are routinely observed have become a net source of carbon-containing greenhouse gases because microbial activity is continuing well into winter after plants go dormant. NOAA Climate.gov drawing. Permafrost map from NSIDC.
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Courtesy Kelley Elliott, NOAA

Ocean acidification impact on pteropods

Pteropods, or sea butterflies, are a vital food source for salmon and other commercially 

important fish. Shown here in laboratory conditions are (left) a pteropod that has lived for 

six days in normal waters and (right) a pteropod showing the effects of living in acidified 

water for the same time period. The white lines indicate shell dissolution and explain why 

ocean acidification is often called “osteoporosis of the sea.” (NOAA)

One species of shrew is now invading north into the Arctic, setting off a major reorganization of animal 

communities at the top of the world. Accelerating climate change in the Arctic is spurring the northward invasion of shrews, bringing an array of tapeworms and other parasites, according to authors of an 

essay in 2016’s report card, “Small species indicate big changes: Shrews and their parasites. www.arctic.

noaa.gov/Report-Card/Report-Card-2016/ArtMID/5022/ArticleID/268/Shrews-and-Their-ParasitesSmall-Species-Indicate-Big-Changes” Phil Myers, photographer; copyright holder/Museum of Zoology, University of Michigan-Ann Arbor

Methane bubbles trapped in ice on Abraham Lake, in Alberta, Canada, during winter 2016-17.

Photo by Flickr user juneaidrao, used under a Creative Commons license .

Courtesy Joel Garlich-Miller, USFWS
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128

Following the 

Ocean Unicorn

Is this a unicorn? Not really—it’s actually a drawing of a narwhal, a 

whale that spends its entire life in the Arctic. Most male narwhals have 

a tooth in their upper jaw that forms a long tusk. For several centuries, 

northern traders sold narwhal tusks throughout Europe, claiming they 

were unicorn horns. One of the largest groups of narwhals spends most of 

the winter in Ba n Bay, between Canada and the western coast of Greenland. This is an unusual area, because while most of the Arctic is getting 

warmer, air and sea surface temperatures near western Greenland are 

getting cooler, and sea ice concentrations in Ba n Bay have increased 

signifi cantly since 1953. But at the same time, temperatures in deep 

water below 1,200 feet in Ba n Bay are slowly getting warmer. 

What You Will Do

Make a poster about narwhals, how they are being affected by climate change, 

how climate change may affect humans, and what we can do about it.

This is important, because the deep water in Ba n Bay is part of a 

worldwide system of deep currents that connect Earth’s largest oceans. 

Temperature is one of the things that makes this system work, and some 

scientists are worried that changing temperatures in the Arctic could 

cause the system to slow down or even stop working entirely. Even though 

it’s getting warmer, the Arctic is still a di cult place to do scientifi c work, 

and it has been almost impossible for scientists to gather very much 

information on deep ocean temperatures.

Believe it or not, narwhals may help solve this problem! Narwhals in 

Ba n Bay often dive more than 4,500 feet deep to fi nd food. And 

they do this during the winter when it is impossible for scientists to do 

deep ocean research in the Arctic region. NOAA’s Ocean Explorer 2006 

Arctic Winter Ecosystem Exploration attached instrument packages 

From An account of the Arctic regions with a history and description of the northern whalefi shery by W. Scoresby. 1820. Courtesy NOAA..
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called “satellite tags” to narwhals to record 

temperature and depth during deep dives 

for food. A transmitter in each tag sends the 

information to a satellite, and the satellite 

sends the information back to Earth to give 

scientists the fi rst-ever data on deepwater 

winter temperatures in Ba n Bay. 

Unfortunately, narwhal populations may be 

declining. There are several possible reasons for 

this:

• Hunting by indigenous Arctic peoples (which 

means people who have lived in the Arctic 

for hundreds of years);

• Increased harvest of fi sh by humans, reducing the amount of food available for 

narwhals; and/or

• Climate change. 

Ba n Bay is one of the few places in the Arctic 

where sea ice is increasing; and this causes 

problems for narwhals because it reduces the 

amount of open water needed by the whales, 

and increases the danger that they may become 

trapped in the ice.

Does this seem that what’s bad for 

the narwhals might be good for the 

polar bears? Not really, because 

not enough ice where ice should be 

is just as bad as too much ice where 

ice should not be. Remember, too, 

that even though the average temperature in the 

Arctic is going up, there can still be places that 

are colder than the average; but these colder 

temperatures are balanced by temperatures in 

other places that are higher than the average.

Just as narwhals are helping scientists study 

the deep ocean, they can also help you tell 

other people about global climate change.

What You Will Need

❒ Copies of “Images for Narwhal Posters”

❒ Information from the introduction for this 

activity, the “Narwhal Fact Sheet” and “Is Our 

Climate Changing?” (page 137)

❒ Crayons, colored markers, or colored pencils

❒ Poster board

❒ Scissors

Warning

 Be careful with sharp scissors!

How to Do It

1. Use the images and information to create a 

poster that explains about narwhals and how 

they are being aff ected by climate change. 

You may also want to include information 

about why climate change is important to us, 

what we can do about it, and possibly some 

ideas and information from the “What are the 

Impacts of Shrinking Polar Ice Caps? on page 

121, since it also deals with climate change 

and Arctic animals.

2. Show your poster at school, to your parents, 

and to other groups. The more people know 

about climate change and how it aff ects life 

on Earth, the more they will take action to 

protect Earth’s ecosystems.

Want to Do More?

Visit www.oceanexplorer.noaa.gov/

explorations/06arctic/welcome.html for 

more information about narwhals and NOAA’s 

Ocean Explorer 2006 Arctic Winter Ecosystem 

Exploration. 

This activity was adapted from “The Ocean 

Unicorn” (10 pages, 292 kb) by Mel Goodwin, PhD and science writer, Charleston, SC; 

from the Ocean Explorer 2006 Arctic Winter 

Ecosystem Exploration [www.oceanexplorer.

noaa.gov/explorations/06arctic/background/edu/media/unicorn.pdf]

Courtesy Kristin Laidre
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130

• Narwhals belong to the genus Monodon and the 

species monoceros.

• Narwhals belong to the class Mammalia and the 

order Cetacea.

• Male and female narwhals have two teeth, in the 

upper jaw. In most female narwhals, the teeth 

never erupt through the gum. In most males, 

the left tooth forms a long tusk. In rare cases, 

males may develop two tusks, and females 

may also develop one or two tusks.

• The most widely accepted explanation for the 

function of the narwhal’s tusk is that it is 

possibly involved with mating behavior or 

as a weapon in battles over possession of 

females.

Narwhal Fact Sheet

• Narwhals spend their entire lives in the Arctic.

• Narwhals eat fi sh (including polar cod, 

Greenland halibut, fl ounder, salmon, 

and herring), cephalopods (squids and 

octopuses), and shrimp.

• Narwhals can dive to depths of 4,500 feet or 

more.

• Narwhals need to come to the surface of the 

ocean periodically, because they are mammals and must surface to breathe air.

• Normally, a female narwhal produces one calf 

at a time.

• Narwhals seem to prefer deep water near 

loose pack ice. In the summer, they occupy 

deep bays and fjords in the Canadian High 

Arctic and Greenland. As winter approaches, 

narwhals migrate into the pack ice of Baffi n 

Bay, the northern Davis Strait, and adjacent 

waters.

• Narwhals can live for 50 years or more.

• Narwhals have been traditionally hunted 

by indigenous Arctic peoples who value 

them as a staple food (the skin is rich in 

vitamin C), as well as for their tusks (though 

international eff orts to control the global 

ivory trade may have reduced tusk sales in 

recent years). Narwhal sinews (tissues that 

attach muscles to bones) may also be used as 

thread.

Several male narwhals in 

West Greenland. Courtesy 

Mads Peter Heide-Jorgensen
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Images for Narwhal Posters

Melville Bay is the site of many active glaciers. The area is filled with large icebergs that 

dwarf the Sila, the boat used for narwhal tagging/tracking. Courtesy Kristin Laidre.

Narwhals. Courtesy Kristin Laidre

Male narwhals. Courtesy Mads Peter Heide-Jorgensen

Narwhals. Courtesy Kristin Laidre
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132

Instrument packages called “satellite tags” are 

attached to narwhals by plastic coated wires 

affixed to two nylon pins (1/4 inch diameter) 

inserted through the dorsal ridge on the 

whales’ back (the whales shed the tags after 

several months; 14 months is the longest 

time a tag has stayed on a whale). An alternative method of attaching the tags involves 

placing the tags into small cylinders that are 

implanted in the layer of blubber along the 

whales’ back using hand-held thrown poles 

similar to harpoons. Tags attached using the 

latter methods are only expected to provide 

data for four to five weeks.

Satellite-based locations for three narwhals 

tagged in Melville Bay in September 2006. Whales 

are still in their coastal summering grounds but 

will migrate offshore by mid-November. Courtesy Kristin Laidre

Narwhal wintering areas (pink) in Baffin Bay and 

Davis Strait. Courtesy Kristin Laidre Male narwhal (ID 3964) captured and satellite tagged. 

You can see where he went in the map to the left. 

Courtesy Kristin Laidre

Does Tagging Hurt Narwhals? 

Researchers say “No, we have quite good 

evidence that tagging does not hurt them—both 

in the short and long term.” Satellite tags are 

only attached into blubber where there are few 

nerve endings, and the whales do not react at 

all when he tags are attached. As soon as the 

whales are released, they immediately resume 

normal behavior. In addition, whales that have 

been recaptured several years after tagging show 

no evidence of being harmed by the tagging 

process.
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Make an Edible 

Coral Reef

You have probably seen pictures of coral reefs before—lots of colors, fi shes, and weird looking shapes! Coral reefs are not only beautiful to look 

at; they are also home to thousands of other species. In fact, scientists 

estimate that there may be another one to eight million undiscovered 

species living in and around reefs! Coral reefs support more species per 

square foot than any other marine environment. This abundance of living 

organisms is key to fi nding new medicines for the 21st century. Many 

drugs are now being developed from coral reef animals and plants as 

possible cures for cancer, arthritis, human bacterial infections, viruses, 

and other diseases.

Coral reefs are important for other reasons as well. Coral reefs are a 

breeding ground for many fi sh and other species, and millions of people 

and thousands of communities all over the world depend on coral reefs 

for food. In the United States, coral reef ecosystems support hundreds 

of commercial and recreational fi sheries worth more than 200 million 

What You Will Do

Make an edible model of a coral reef!

dollars. Local economies receive billions of dollars from visitors to reefs 

through diving tours, recreational fi shing trips, hotels, restaurants, and 

other businesses based near reef ecosystems. Coral reefs protect shorelines against waves, storms and fl oods, and help prevent loss of life, 

property damage and erosion. 

Despite their importance, many of Earth’s coral reefs are in trouble. Severe storms, water pollution, overfi shing, disease, global climate change, 

and ships running aground are some of the things that have destroyed or 

badly damaged many reefs. Because of these threats, coral reefs and all 

of the creatures that call them home may be in danger of disappearing if 

something isn’t done to protect them. NOAA is one of many organizations 

Spanish hogfi sh at reef.

Courtesy Florida Keys National Marine Sanctuary

You have probably seen pictures of coral reefs before—lots of colors, fi sh- dollars. Local economies receive billions of dollars from visitors to reefs 

Make an Edible 

Coral Reef
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134

participating in the U.S. Coral Reef Task Force, 

which was established in 1998 to protect and 

conserve coral reefs. Satellites are being used 

to map shallow U.S. coral reefs, as well as to 

watch for high sea surface temperatures that 

can damage corals and to detect harmful algae 

that can smother reefs. NOAA’s National Undersea Research Program does research projects 

to learn more about coral reefs, and restores 

damaged reefs in marine reserves and among 

deep sea coral banks.

Coral reefs need your help, too! More people 

need to understand why coral reefs are important and what needs to be done to protect them. 

Here’s a tasty way to start a conversation about 

coral reefs.

What You Will Need:

r One half sheet cake; if you want to bake your 

own cake you will need a box of cake mix and 

other ingredients listed on the box 

r Icing in various colors

r Food coloring

r Marshmallows, licorice whips, small cookies, 

candy sprinkles, or other edible materials 

for modeling coral reef animals and habitat 

features

Warnings:

1. Get an adult to help with baking.

2. Don’t eat too much!

3. Wash your hands before handling food! If more 

than one person is involved with this activity, 

you may also want to wear disposable gloves.

How to Do It:

1. If you aren’t familiar with coral reefs, read the 

sidebar “What is a Coral Reef?” You may also 

want to look at books about coral reefs or 

check out the Web sites listed under “Want to 

Do More?” 

A healthy coral reef ecosystem contains 

thousands of species, so you can’t really 

include everything in your model. Instead, 

plan a model that is colorful and interesting, 

using the images on these pages for ideas. 

Remember, the main idea is to create a model 

that will help start a conversation about 

coral reefs (and is also good to eat!).

Before you actually make your model, make 

a list of what plants or animals you want to 

include, and what materials will be used to 

show them on the model. Mounds of icing can 

be used for boulder-shaped corals. When icing 

mounds have hardened they can be sculpted 

to form caves and overhangs. Small cookies 

could represent plate-shaped corals. Coconut 

colored with green food coloring could be 

used for seagrass. Sponges could be modeled 

with small pieces of sponge cake (of course). 

Licorice whips could represent branching 

corals. Gummy fish or fish crackers on toothpicks can represent fish. Raisins or chocolate 

chips might be sea urchins. Of course, there 

are many more possibilities, and you probably 

already have a pretty good idea of things you 

could use in your model. 

2. If you plan to bake you own cake, mix the batter 

according to instructions on the box, and bake 

the cake in an oversized flat pan like a broiler 

pan or turkey roasting pan. Your cake will probably take less time to bake than the time stated 

on the cake mix box, because your cake will be 

thinner than usual.

3. The flat cake is the base of your model reef. 

Add the features you planned in step 1 to 

complete the model. This is a lot of fun to do 

with two or three other people, but be sure 

you wash your hands and wear disposable 

gloves so you can safely eat the model later.

A purple soft coral. Courtesy Florida 

Keys National Marine Sanctuary
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4. Show your model to your friends, parents, 

school, or other groups, and talk about why 

coral reefs are important, why they are in 

trouble, and what we can do to help save 

them. If you are using your model at school, 

your teacher may be able to arrange for you 

to make a presentation about coral reefs 

to another group of students, perhaps a 

younger class. When you have fi nished your 

presentation, you can say, “Now it is time 

for us to have a direct interaction with this 

model reef.” Which means everyone can eat 

the cake!

Want to Do More?

www.coris.noaa.gov/– Information about coral 

reefs from NOAA’s Coral Reef Information 

System

oceanservice.noaa.gov/facts/thingsyoucando.

html – Things You Can Do to Protect Coral 

Reefs, a National Ocean Service fact sheet 

www.coralreef.noaa.gov/– NOAA’s Coral Reef 

Conservation Program

coralreefwatch.noaa.gov/satellite/education/ – 

Coral Reef Conservation Program, Education 

and Outreach

oceanservice.noaa.gov/education/tutorial_corals/welcome.html – Coral Tutorial from 

NOAA’s National Ocean Service

www.teachoceanscience.net/teaching_resources/education_modules/coral_reefs_and_climate_change/how_can_you_help_coral_

reefs/ - Teacher resources from Teach Ocean 

Science

Grey snappers at the reef. 

Courtesy Florida Keys National Marine Sanctuary

Barrel sponges.

Courtesy Florida Keys National Marine Sanctuary Butter hamlet fi sh with soft corals.

Courtesy Florida Keys National Marine Sanctuary

Elkhorn coral and a white spotted fi lefi sh.

Courtesy Florida Keys National Marine Sanctuary
noaa.gov

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136

Corals are animals that do not have backbones, 

and are related to jellyfish. The large boulders 

that we see in pictures of coral reefs are colonies 

of many individual coral animals called polyps 

(“PAH-lips”). Polyps are made of an outer cell 

layer called epidermis (“ep-ih-DERM-iss”) and 

an inner cell layer called gastrodermis (“gas-troDERM-iss”), with a jelly-like substance called 

mesoglea (“mez-oh-GLEE-uh”) in between. Each 

polyp makes its own cup-shaped skeleton called 

a calyx (“KAY-lix)” from limestone (calcium 

carbonate). The base of the calyx is called the 

basal plate, and the outer walls of the calyx are 

called the theca (“THEE-kuh”). Vertical partitions 

called septa extend part-way into the cup from 

the inner surface of the theca. The outer surface 

of the theca is covered by the soft tissues of the 

coral. Polyps have a mouth surrounded by a ring 

of arms called tentacles. The tentacles have 

stinging cells called nematocysts (“nee-MAToh-sists”) that polyps use to capture food. Most 

corals are carnivorous, and feed on small floating 

animals or even fish. Many corals also feed by 

collecting very small bits of floating material 

on strings of mucous, which they pull into their 

mouths. Food is digested by digestive filaments 

in the stomach. Waste is expelled through the 

mouth. 

Most reef-building corals have very small polyps, 

about one to three millimeters in diameter; but 

all of the polyps in a whole colony can make a 

limestone rock that weighs several tons! Individual polyps in a coral colony are connected by 

a thin band of living tissue called a coenosarc 

(“SEE-no-sark”).

As the polyps grow and multiply, the coral colony 

may become shaped like boulders, branches or 

flattened plates. Some corals form tall columns, 

others resemble mushrooms, and some simply 

grow as a thin layer on top of rocks or the skeletons of dead corals.

When corals reproduce, they release free-swimming larvae that can be carried many miles away 

by ocean currents. A new reef begins when these 

larvae attach to underwater rocks or other hard 

surfaces along the edges of islands or continents. 

As the corals grow and expand, other animals 

and plants join the reef system. Sponges and soft 

corals (sea fans and sea rods) are particularly visible on many reefs. Various types of seaweed and 

algae are also important. Some of algae produce 

limestone structures that add to the overall reef 

structure. Fishes and many other types of animals 

take advantage of shelter provided by the reef, and 

feed on algae and bacteria that grow on surfaces 

within the reef.

Most reef-building corals also contain algae that 

live inside the soft tissue of the polyp. These 

algae are called zooxanthellae (pronounced 

“zoh-zan-THELL-ee”), and like other algae are 

able to use energy from the sun to make food. So 

the corals and algae have a relationship that is 

called “mutualistic.” This means that the coral 

and algae both benefit from the relationship: The 

coral gives the algae a protected environment 

and chemicals the algae need to make food. In 

return, the algae provide the coral with food, 

oxygen and help remove wastes from the coral. 

This relationship allows corals to grow in waters 

that do not have much food available. 

Besides providing corals with food, zooxanthellae are also responsible for the bright colors of 

many corals. When corals are stressed, particularly by high temperature, the polyps lose their 

zooxanthellae and the coral colony becomes 

completely white. This is often called “coral 

bleaching.” Coral polyps can live for a short period of time without zooxanthellae, but if bleaching lasts too long the coral may die.

A colony of star coral. Courtesy Commander William Harrigan, 

NOAA Corps (ret.), Florida Keys National Marine Sanctuary

What is a Coral Reef?
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Coral reefs face numerous hazards and 

threats. Among these are:

Excessive Fishing – Many coral reefs have 

very few fishes because they have been 

captured for food or aquariums. In 

healthy reef ecosystems, fishes graze 

on algae. Without the fishes, algae can 

grow rapidly and smother coral polyps. 

Destruction of Habitats – Some fishing 

methods destroy living reefs. Bottom 

trawling is extremely destructive. In 

some countries, fishermen use dynamite to 

stun fish, which also kills corals and damages 

the reef structure.

Invasive Species – Plants and animals that do not 

naturally live on reefs can damage the reef 

ecosystem. Some invasive seaweeds grow 

rapidly and smother reef-building corals.

“The Rise of Slime” – Many reefs are becoming 

overgrown with marine algae and films of 

bacteria. Part of the problem is pollution. 

In the Gulf of Mexico, for example, fertilizer 

pollution causes excessive growth of algae 

that is responsible for a “dead zone” the size 

of New Jersey. Habitat destruction, overfishing, and pollution also kill natural filters like 

oysters and sponges that normally help clean 

the water.

The 3RD Global Coral Bleaching Event 2014-2017 

This is by far the longest and most widespread event in recorded history. In 1998, 

a huge underwater heatwave killed 16% 

of the corals on reefs around the world. 

Triggered by the El Niño of that year, it 

was declared the first major global coral 

bleaching event. The second global bleaching event that struck was triggered by the 

El Niño of 2010. The US National Oceanic & 

Atmospheric Administration (NOAA) announced the third global bleaching event 

in October 2015 and it has already become 

the longest event recorded, impacting some 

reefs in consecutive years.

The new phenomenon of global coral bleaching events is caused by ocean 

warming (93% of climate change heat is 

absorbed by the ocean). Corals are unable 

to cope with today’s prolonged peaks in 

temperatures – they simply haven’t been 

able to adapt to the higher base temperatures of the ocean. Although reefs 

represent less than 0.1 percent of the 

world’s ocean floor, they help support 

approximately 25 percent of all marine 

species. As a result, the livelihoods of 

500 million people and income worth 

over $30 billion are at stake.

The two previous events caught us relatively unprepared. The world simply didn’t have 

the technology, understanding or teams in 

place to reveal and record them properly. 

This year is different—sponsored by an 

insurance company interested in the risk 

resulting from ocean warming, the XL Catlin 

Seaview Survey, running off predictions issued by NOAA’s Coral Reef Watch programme 

(which have proven to be accurate), has 

been able to respond quickly. A major global bleaching event is considered one of the 

most visual indicators of climate change. 

Working together with science partners 

around the world, these free resources have 

been developed to help you research and 

communicate this important issue, and to 

ensure this event doesn’t stay out of sight 

and out of mind.

www.globalcoralbleaching.org/#overview

Why are Coral Reefs in Trouble?

The Death of a Coral Reef. This image shows the same reef in 

American Samoa before, during, and after a coral bleaching event. 

Photographed by The Ocean Agency / XL Catlin Seaview Survey / 

Richard Vevers.
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Why do corals matter? 

A coral reef is like an oasis in a desert. Corals provide 

both food and shelter for a staggering amount of 

marine life. Although coral reef ecosystems represent 

less than 0.1% of the area of the ocean, approximately 25% of all marine species relies on them. They are 

especially important as a nursery for juvenile fish until they are large enough to venture into open-ocean. 

Losing a coral reef can have a dramatic impact on 

local food,fisheries and livihoods. About 500 million 

people globally depend on such fisheries.

What is coral bleaching? 

Coral bleaching is the process by which corals lose 

their colouration and turn a ghostly white. This 

happens when they become overly stressed especially 

when exposed to warmer than normal temperatures 

and excessive sunlight (normally over 4-6 weeks).

What happens when corals bleach? 

When corals bleach they are actually expelling the 

brown algae that they grow within their body tissues. 

Corals expel algae because high temperatures cause 

the algae to produce toxic compounds. The expulsion 

of algae makes the corals appear a brilliant white—

which is due to skeletons being visible through their 

translucent coral tissue.

How often does coral bleaching occur? 

Bleaching is becoming increasingly common throughout the coral reef regions of the world as a direct 

result of warming oceans. Nowadays there is at least 

some limited coral bleaching reported each year especially during summer months, although the major, 

global events that span multiple oceans are usually 

associated with natural variability (e.g. El Niño conditions) building on top of seas that ar now warmer 

because of climate change. 

What is the connection between bleaching and climate 

change?

Coral bleaching is one of the most visual indicators of 

thermal stress due to climate change. It is a phenomenon caused by ocean warming. The oceans have 

absorbed 93% of the heat from climate change and 

are now significantly warmer than they were 50 years 

ago. The heat that is causing reefs to turn white represents the momentum of climate change—it will increasingly impact our weather, climate and rainfall for 

decades to come until a new equilibrium is reached. 

This hidden energy could also trigger runaway heating 

if the ocean’s methane deposits are released. It is 

why coral reefs are often referred to as “the canary in 

the coalmine.”

What is Mass or Global Coral Bleaching? 

Mass coral bleaching is where whole reef systems 

bleach and not just a few individual corals. This was 

first recorded in 1979. It is thought that a tipping 

point was reached around that time when the shortterm temperatures that normally accompany El Niño 

events began to exceed the temperatures that corals 

could tolerate.

How damaging are mass bleaching events? 

Mass bleaching events can be extremely damaging. A 

reef can turn from a coral dominated reef to an algae 

dominated reef in the space of a few months – a process that can take decades or longer to reverse. The 

Galapagos Islands was one of the first places where 

mass bleaching and mortality was first documented. 

the reefs there lost over 95% of their coral during the 

1982 event. 

Why is coral bleaching associated with El Niño? 

El Niño events result in higher than normal ocean 

temperatures in large parts of the world. This causes 

higher levels of stress on coral reefs. During the warm 

season, the higher than normal ocean temperature, 

combined with additional seasonal heating and sunlight, is often enough to now cause corals to bleach.

Does bleaching only occur when there is an El Niño? 

Major global events have only happened in El Niño 

years to date, however the baseline temperature of 

the ocean is now high enough that we see some mass 

bleaching every year. It is now only a matter of time 

before we have a global event that is not triggered in 

an El Niño year.

Can anything be done to reduce the risk of corals 

bleaching?

The coral’s ability to recover often depends on how 

healthy it was before the event. Coral reefs can be 

‘prepared’ for bleaching events by ensuring local 

stressors, such as overfishing and pollution, are minimised. 

How does the XL Catlin Seaview Survey help? 

The XL Catlin Seaview Survey team is conducting 

the most extensive visual and scientific survey of 

the world’s coral reefs. The Survey’s images are are 

available for expert insight and comment on corals, 

bleaching and ocean change.

Coral Bleaching: Essential Facts

Coral bleaching in the Maldives captured by The Ocean Agency / XL 

Catlin Seaview Survey in May 2016

This Essential Guide to Coral Bleaching was prepared by Professor Ove-Hoegh-Guldberg, XL Catlin Seaview Survey’s Chief Scientist and 

Director of the Global Change Institute at the University of Queensland, Australia. www.globalcoralbleaching.org/#essential-facts
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A habitat is a place where an animal or plant lives and grows. How many 

habitats do you see in this picture? There are thousands! This is because 

the branched and wrinkled shape of the sponges and corals produce 

many diff erent spaces of many sizes that can provide shelter to other 

organisms. The variety of habitats found on coral reefs is one of the reasons that a square foot of coral reef supports more species than any other 

marine environment. 

Here’s a way to show how coral reefs create a wide variety of habitats by 

repeatedly dividing a space into smaller and smaller pieces.

What You Will Need:

❒ Colored pencils or fi ne-point markers

❒ Ruler

❒ Copy of “Triangle Graph Paper”

What You Will Do

Make a Sierpinski triangle that shows how 

repeatedly dividing a fixed space 

produces an infinite series of 

increasingly smaller spaces. Sponge, coral, and soft coral.

Courtesy Florida Keys National Marine Sanctuary

Now THAT’s Complex!
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How to Do It:

1. Begin by drawing an equilateral triangle measuring 16 cm on each side. This triangle is 

drawn in red on the “Triangle Graph Paper.”

2. Find the midpoint of each side (8 cm), and 

join these midpoints as shown in Step 1. 

3. Shade the triangle in the middle as shown in 

Step 2. 

4. Find the midpoints of each side of the three 

outer triangles (4 cm), and join these as 

shown in Step 3. 

5. Shade each of the middle triangles as shown 

in Step 4. 

6. Continue this process three more times, until 

the midpoints measure 0.5 cm, shading 

the middle triangles each time, until the 

drawing appears similar to Step 5. You 

have made many different-size “habitats,” 

simply by dividing the space over and over 

again. Theoretically, you could continue 

this process indefinitely to make an infinite 

number of habitats!

Want to Do More?

The Sierpinski Triangle is an example of fractals, 

which are geometric figures that have special 

properties and are often found in nature. For 

more information about fractals, visit math.rice.

edu/~lanius/frac/.

This activity was adapted from “Architects of Seamount 

Ecosystems” by Mel Goodwin, PhD, Marine Biologist and 

Science Writer, Mt. Pleasant, SC.; from the Ocean Explorer 

2004 Gulf of Alaska Seamount Expedition oceanexplorer.

noaa.gov/explorations/04alaska/background/edu/media/

goa04_form.pdf

Step 1

Step 2

Step 3

Step 4

Step 5
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Triangle Graph Paper
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Fixing Our Earth

After four centuries as a major center of ocean commerce and 

naval power, the Elizabeth River is the most polluted waterway on 

the Chesapeake Bay for some cancer-causing chemicals.

Courtesy Captain Albert E. Theberge, NOAA Corps (ret.)

Adobe Creek in Sonoma County, California was once alive with 

salmon and steelhead trout; but after years of pollution and neglect, 

state offi cials declared it “dead.” Courtesy NOAA Restoration 

Center

Seagrasses provide food and habitat for different species of fi sh, 

lobster, wading birds, manatees and sea turtles. In Tampa Bay, more 

than 70 percent of seagrass meadows have been destroyed by pollution, coastal development, dredging, and boat propellers. Courtesy 

NOAA Restoration Center

After four centuries as a major center of ocean commerce and Adobe Creek in Sonoma County, California was once alive with Seagrasses provide food and habitat for different species of fi sh, 

There are hundreds of stories about damage to 

coral reefs, rivers, fi sheries and other resources 

caused by storms, oil spills, chemical pollution, 

and many other events. 

So, is there anything we can do?

Yes! We can help restore habitats and save 

many species!

NOAA has worked with more than 2,500 groups 

throughout the U.S. to protect and restore 

marshes, wetland forests, oyster reefs, seagrass 

beds, beaches, and tidal streams that have 

been damaged by natural events and human 

activities. Restoration projects include:

What You Will Do

Get involved in a project to restore damaged natural resources

• Removing invasive species

• Repairing damaged habitats

• Cleaning up pollution

• Restoring natural ecosystem processes such 

as water fl ow

• Re-introducing native organisms

• Monitoring activities to evaluate long-term 

success
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Local middle and high school students grew more 

than 100,000 bushels of seed oysters that were used 

to successfully restore oyster reefs in the Elizabeth 

River, Portsmouth, VA. Courtesy NOAA Restoration 

Center

Students in the Tampa Bay area grow marsh grasses 

and seagrasses, and assist with monitoring and planting to restore damaged habitats. Courtesy Tampa 

BayWatch

Students at Casa Grande High School built the only student run fi sh hatchery in the lower 48 states, removed 

trash from Adobe Creek, planted trees, so that Steelhead 

and Chinook salmon are once again spawning in the 

steam. Courtesy NOAA Restoration Center

Local middle and high school students grew more Students at Casa Grande High School built the only stu- Students in the Tampa Bay area grow marsh grasses 

What You Will Need

❒ Good ideas

❒ Desire to make things better

❒ Willingness to get involved

Warning

Work on this project with an adult partner! Be 

sure you have permission and expert advice before starting any restoration activities.

Here’s how you can start helping 

to fix our Earth!

Kids play a big part inmany restoration projects!
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Some Organizations Involved with 

Habitat Restoration Projects

American Littoral Society

American Rivers

American Sportfishing Association

Chesapeake Bay Foundation

Coalition to Restore Coastal Louisiana

Connecticut River Watershed Council

Conservation Law Foundation

Ducks Unlimited

EarthCorps

Gulf of Maine Council on the Marine 

Environment

Gulf of Mexico Foundation

Institute for Fisheries Resources

Institute For Sustainable Forestry

National Fish and Wildlife Foundation

North Carolina Coastal Federation

Ocean Trust/National Fisheries Institute

Save the Bay (Narragansett Bay)

The Nature Conservancy

Tampa Bay Watch

Trout Unlimited

How to Do It

1. Visit the Web sites listed on “NOAA’s 

Restoration Programs.” Read some of the 

case studies to get ideas about different 

kinds of restoration projects. Also, check out 

the “Volunteers” page at NOAA’s Restoration 

Portal www.habitat.noaa.gov/highlights/

hlrestorehabitatsoutheast.html

2. Look over “Some Organizations Involved with 

Habitat Restoration Projects.” Check your 

local telephone directory to see if any of 

these organizations have an office nearby. If 

so, give them a call and ask about restoration 

projects in your area. If not, contact NOAA’s 

Fisheries Restoration Center (see the contact 

list at www.habitat.noaa.gov/restoration/

connection/partnerships.html).

3. Talk to your parents, friends, teachers, 

and other groups about getting involved 

in a restoration project. Many successful 

restoration projects begin with one person 

who wants to make things better. Maybe you 

can be that person!

NOAA’s Restoration Programs

The Damage Assessment and Restoration Program focuses on events such as oil spills, release 

of toxic chemicals, or ships that run aground. 

www.darrp.noaa.gov/

The Community-Based Restoration Program 

works with local partners to restore fishery habitats and encourage conservation of living marine 

resources. www.habitat.noaa.gov/restoration/

programs/crp.html

The Office of Response and Restoration investigates natural resource damage, plans restoration 

projects, and helps local groups design monitoring plans to measure the success of restoration 

projects. response.restoration.noaa.gov/

Through the National Coastal Zone Management 

Program, NOAA partners with state coastal zone 

management programs to develop habitat restoration plans and carry out a variety of restoration 

projects. coast.noaa.gov/czm/

The National Estuarine Research Reserve System 

works with local and state partners as well as 

other NOAA offices and federal agencies carry out 

habitat restoration projects based on scientific 

observations and historical analysis of ecosystems. coast.noaa.gov/nerrs/

The Coral Reef Conservation Program provides 

funding and technical assistance to NOAA offices 

and partner groups to support restoration, monitoring, and research on the effectiveness of coral 

reef restoration methods. coralreef.noaa.gov/
“Knowledge of the oceans is more than a matter 

 of curiosity. Our very survival may hinge upon it.”

President John F. Kennedy, Jr., March 1961 message to Congress.
United States Department of Commerce

National Oceanic and Atmospheric Administration (NOAA)

www.noaa.gov

NOAA’s National Ocean Service

Communications and Education Division

Discover Your World with NOAA

https://oceanservice.noaa.gov/education/discoveryourworld

U.S. Government 2017