the

A science journal for elementary school students

Investi-gator

Summer 2009
2 The Investi-gator • http://www.scienceinvestigator.org 

Jessica Nickelsen 

Editor

Cradle of Forestry Interpretive Association

Babs McDonald

Co-Editor

U.S. Forest Service

Washington D.C.

Barbara McGuinness

Co-Editor

U.S. Forest Service

Northern Research Station

Michelle Andrews

Education Outreach Specialist

University of Georgia

Nickola Dudley

Design/Layout

Asheville, NC

U.S. Forest Service scientists 

highlighted in this journal:

Christian Giardina

David Bengston

Paula Murakami

John Campbell

Paul Schaberg

Cooperating scientists 

highlighted in this journal:

Jenna Fletcher

Kristen Nelson

Lynn Christenson

Myron Mitchell

Peter Groffman

Lingli Liu

John King

John Shane

Abby van den Berg

U.S. Forest Service

Abigail Kimbell

Chief

Ann Bartuska

Deputy Chief, Research and Development

Michael T. Rains

Director, Northern Research Station

John Sebelius

Director, Science Quality Services

Jim Hubbard

Deputy Chief, State and Private Forestry

Safiya Samman

Director, Conservation Education

Linda Ries

Conservation Education Coordinator, Retired

Cradle of Forestry Interpretive Association

Alex Comfort

Executive Director

Bill Alexander

Chairman

The Investi-gator 

Northern States Edition Volume 1, Number 1 • Summer 2009

With thanks to:

Holly Rutledge

Educational Consultant

Gwinnett County, Georgia

Loretta Brewster

Teacher

Myers Elementary School, 

Hall County, Georgia

Gayla Pierce

Teacher

Lyman Hall Elementary 

School, Hall County, 

Georgia

Project Learning Tree

Washington, D.C. 
The Investi-gator • http://www.scienceinvestigator.org 3

Editorial Review Board at Work.....................................................4

Who Are Scientists?........................................................................5

Welcome to the Northern States 

Edition of the Investi-gator!............................................................6

About the Investi-gator...................................................................7

Features

Are You Red-dy To Change?

Learning What Things Affect Leaf Color Change.................................................................8

No Littering O-Zone

How Rising Ozone Levels Affect Tree Growth.................................................................. 16

Out of the Penalty Box

Protecting the Environment Through Policies.................................................................... 25

Snowed In?

A Closer Look at Soil Activity in the Wintertime............................................................... 35

Word Search and Crossword Puzzles....................................................................................45

Note to Educators..................................................................................................................48

Lesson Plan for the Investi-gator..........................................................................................49

Assessment Rubric................................................................................................................51

Evaluations............................................................................................................................52

Possible Answers to Reflection Questions............................................................................55

Education Standards..............................................................................................................58

What is the U.S. Forest Service? ..........................................................................................59

What is the Northern Research Station? ...............................................................................59

Editorial Review Boards......................................................................................... back cover

Contents
4 The Investi-gator • http://www.scienceinvestigator.org 

Editorial Review Board At Work

Comments about individual articles in this edition from the Investi-gator editorial review boards 

Lyman Hall Elementary and Myers Elementary

Hall County, Georgia

I liked the 

FACTivity 

(for the ozone 

article).

I think that it is a 

great article for 

kids my age.

I liked the 

glossary but 

would like to have 

the word defined 

on the page 

where the word is 

located.

Number 

crunch was 

confusing.

I liked the layout, 

but I’d like color 

pictures.

You should give 

a little more 

information in the 

captions.

It would be good 

to have an index 

at the end.

Make sure to 

show pictures 

of the important 

facts.
The Investi-gator • http://www.scienceinvestigator.org 5

Scientists are people who collect and evaluate information 

about a wide range of topics. Some scientists study the 

natural environment. 

To be a successful scientist, you must:

Who Are Scientists?

Be curious: 

You must be interested in learning.

Be enthusiastic:

You must be interested in a particular 

topic.

Question everything:

You must think about what you read 

and observe.

Be open-minded:

You must be willing to listen to 

new ideas.

Be careful:

You must be accurate in everything 

you do.
6 The Investi-gator • http://www.scienceinvestigator.org 

Welcome to the Northern States Edition of the Investi-gator!

North Pole

South Pole

Have you ever thought about where you 

live on Earth? Earth is like a round ball which 

spins on its axis (aks is). Earth’s axis is an 

imaginary line connecting its north pole and 

its south pole (figure 1). The equator divides 

the northern half of Earth from its southern 

half. Areas near the equator are warmer. 

The position of the sun’s rays keep this area 

warmer. Areas near the poles have a brief 

summer and are cold compared with other 

areas of Earth.

Figure 1. Can you see the line between 

the north pole and the south pole? The 

Earth’s axis is slightly tilted.

Figure 2. The Northeastern United States 

is made up of twenty states.

The land between the poles and the equator 

is different. It is different because the climate

(kli met) changes during the year. The climate 

is the average condition of the weather over 

large areas, over a long time, or both.

In general, areas close to the equator are 

warmer. Areas close to the poles are cooler. 

There are other things that affect an area’s 

climate too, like altitude (al tuh tud) and 

Earth’s ocean currents. Altitude is how high 

an area is above sea level. An area in the 

mountains is cooler than an area closer to 

sea level. The ocean currents affect weather. 

Weather affects climate.

This Investi-gator journal focuses on 

scientists working in a particular area on 

Earth. That area is the Northern United 

States (figure 2). This area has a cool climate 

compared with areas near the equator. 

Because of this, scientists working in the 

Northern United States might study different 

topics than scientists elsewhere. On the other 

hand, some scientific topics are the same, no 

matter where a scientist is working.

In this journal, you will read about four 

topics. The scientists did their research in the 

Northern United States, but the topics are 

important no matter where you live. The first 

article explains why some tree leaves turn 

red in the fall of the year. The second article 

explains how the chemical ozone affected 

trees in Wisconsin. The third article examines 

how we protect the environment through 

policies. The fourth article discusses how soil 

activity changes in the wintertime. Forest 

Service scientists have all been a part of the 

research in these articles. You can learn more 

about the Forest Service by reading the inside 

back cover of this journal, or by visiting 

http://www.scienceinvestigator.org

northern hemisphere

southern hemisphere

equator
The Investi-gator • http://www.scienceinvestigator.org 7

About the Investi-gator

Meet the Scientist

An introduction to the scientist or scientists 

who conducted the research.

Glossary

Possible new terms you will find in the article.

Glossary words are printed in bold in the 

article.

Thinking About Science

A short introduction to something about the 

scientific process that is related to the research 

being presented.

Thinking About the Environment

A short introduction to something about the 

natural environment that is related to the 

research being presented.

Introduction

The part of the written scientific paper that 

introduces the scientific problem or question 

the scientists wanted to solve or answer.

Each article is organized the same way and 

includes the following sections:

Method

The part of the written scientific paper that 

describes how the scientists collected and 

analyzed their data or information.

Findings

The part of the written scientific paper that 

describes what the scientists discovered.

Discussion

The part of the written scientific paper that 

summarizes the research and offers any new 

insights.

Reflection Sections

These are questions placed behind the 

Introduction, Methods, Findings, and 

Discussion sections. The purpose of the 

questions is to help students think about what 

they have read.

FACTivity

This is an activity that you can do in your 

classroom.

The Investi-gator is the newest member of the 

Natural Inquirer family. The Natural Inquirer, 

for middle school students, and the Investigator, for upper elementary level students, 

present science the way scientists most often 

share their research with each other. That 

process is the written scientific paper. 

Each Investi-gator article presents research 

conducted by Forest Service scientists and 

their cooperators. All of the research in the 

Investi-gator is concerned with nature or with 

society’s relationship to nature.
8 The Investi-gator • http://www.scienceinvestigator.org 

Dr. Schaberg

My favorite science experience is 

getting an unexpected result to an 

experiment. Sure, it is great to develop 

a hypothesis (hi poth uh sis) and 

test it in an experiment. A hypothesis 

is an idea that has not been proven 

yet. After you test it, then you may get 

results that show your hypothesis was 

correct. But sometimes you get results 

that are surprising and interesting—

results that teach you something totally 

new. These unexpected results can 

be very exciting. They help open up 

your imagination to unique thoughts 

and lead to the development of new 

hypotheses, new experiments, and new 

insights about the natural world.

Meet the Scientists!

Are You Red-dy

to Change?

Learning What Things Affect Leaf Color Change
The Investi-gator • http://www.scienceinvestigator.org 9

Ms. Murakami

My favorite science experience is the 

opportunity to learn new things! Whether 

it is in the laboratory or in the woods, 

there is always something new to be 

discovered. Recently I spent a lot of time 

figuring out how to measure different 

activity in the leaves of sugar maple trees. 

This was often a difficult and frustrating 

experience. I enjoyed the challenge, 

however, and learned a lot along the way. 

I am anxious to use my newly acquired 

skills to examine fall color and plant 

growth.

Mr. Shane

My favorite science experience was 

figuring out the movements of the moon and 

their effects on the moon’s nightly arc over 

all different moon phases and seasons. It 

was the first thing I figured out completely 

on my own based solely on observation 

and logic. (Sure hope I am right about it!)

Dr. van den Berg

I currently do research on the maple 

sugaring process. One of my favorite 

science experiences is talking to maple 

sugarmakers about the results of a 

research project. It’s a great feeling when 

a study which required lots of time and 

effort to conduct has produced information 

that sugarmakers can apply to benefit 

their own operations!
10 The Investi-gator • http://www.scienceinvestigator.org 

Figure 1a. Examine this 

deciduous tree. Do deciduous 

trees grow in your area? If so, 

name three of them.

Figure 1b. Non-deciduous 

trees do not lose their leaves 

in the winter. They are 

called coniferous trees. 

Thinking About 

Science 

Scientists learn things 

through observation. 

Observation is carefully 

examining something to 

understand it better. Sometimes 

scientists observe plants to 

learn about them. In this 

study scientists observed 

leaves. They observed leaves 

on deciduous (de sij oo us) 

trees. These trees lose their leaves 

in the fall or winter (figure 1a and 1b). 

The scientists observed the change in 

leaf color. They did this because they 

wanted to know why and when leaves 

change color.

Have you ever gone to the mountains to 

see the leaves change color? If so, you are 

not alone. Many people go to the mountains 

to see the leaves change color in the fall. 

Scientists knew that if they can predict when 

leaves will change color, this information will 

help people plan their trips. 

You can see that science helps people in 

many ways. In this case, it can help people 

to enjoy the leaf color change in the fall. 

Science also helps people in other ways. You 

will learn about one of those other ways by 

reading “Thinking About the Environment” 

section. 
The Investi-gator • http://www.scienceinvestigator.org 11

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

Figure 2. This photo shows leaves 

changing color in the fall. To see 

this picture in color, visit http://www.

scienceinvestigator.org.

Introduction 

In the fall, thousands of people visit 

forests. Do you know why? They are 

probably coming to see the leaves change 

color! Leaves change color in the fall. Cooler 

temperatures in the fall cause the chlorophyll 

(klôr o fil) in leaves to break down. 

Chlorophyll is the green color found in plants. 

When chlorophyll begins to break down 

in leaves, the yellow color becomes more 

visible. For some leaves, a red color becomes 

more visible, too. Red color happens because 

there is a build up of a chemical called 

anthocyanin (an thuh si uh nin). 

In this study, the scientists wanted to know 

if air temperature, the length of daylight, or 

the chemicals in the leaves was more likely to 

result in leaf color change in sugar maple trees 

Thinking About the 

Environment

A change in leaf color 

can tell us 

important 

things about 

trees (figure 2). 

Think about a plant in your house. Have you 

ever seen the leaves change color? What 

happens when the leaves change colors? 

Leaf color change could be a sign of trouble. 

Leaves may change color because of sickness 

or stress. Imagine that some tree leaves 

change color in June. What do you think this 

means? It is probably a sign that the tree is 

unhealthy. Understanding leaf color change 

can help scientists understand a tree’s health. 
12 The Investi-gator • http://www.scienceinvestigator.org 

Figure 3. This leaf has beautiful shades 

of red color. To see this picture in color, 

visit http://www.scienceinvestigator.org.

Method 

Sixteen sugar maple trees were studied 

in South Burlington, Vermont (figure 4). 

A number of leaves from each tree were 

collected on 12 different dates. They were 

collected from June to October. Some of the 

leaves were studied for water, sugar, and 

nitrogen content. 

The other leaves were used to measure leaf 

color. To do this, scientists scanned leaves 

with a computerized color scanner (figure 5).

They then used a computer program to 

calculate the amount of red, yellow, and green 

color on each leaf. 

(figure 3). To learn the chemical content 

of the leaves, scientists studied things like 

the amount of nitrogen (nit ro jen), sugar, 

and water. Nitrogen is an element. Oxygen 

is another element you may know. A lot 

of nitrogen is found in Earth’s atmosphere. 

Nitrogen is important to plant life.

Figure 4. Vermont 

is located in the 

northeastern part of 

the United States. 

South Burlington, 

Vermont is located 

in the northwestern 

part of Vermont.

Figure 5. This photo shows 

how the scientists used a 

scanner to determine the 

amount of color in the leaves.

What was the research 

question the scientists wanted 

to answer?

Do you think it is important 

for people to know when fall 

leaf color will be at its most 

colorful? Why or why not?

Courtesy of Paula Murakami

Courtesy of Paula Murakami
The Investi-gator • http://www.scienceinvestigator.org 13

Once they had this information for some 

of the leaves from each tree, they were able 

to estimate the amount of each color on the 

entire tree. The scientists also collected data 

about the length of each day (from sunrise to 

sunset) and air temperature. 

Then the scientists used math. They used 

mathematical equations (e kwa zhuns) to 

understand what they found. An equation is a 

sentence in math like 2 + 2= 4. They looked 

at the data to figure out which information 

would help to predict red color development. 

The scientists compared how the leaf content 

of sugar, water and nitrogen, air temperature, 

daylength, and red color development all 

influenced each other. 

Findings 

The scientists found that the leaves first 

started to show some red in late September. 

Then, the leaves changed more completely 

from green to yellow or red in the middle of 

October. Scientists found that nitrogen was 

the best predictor of red color change. They 

discovered that leaves with less nitrogen 

turned red earlier. Also, those leaves turned a 

more complete red than other leaves (figure 6).

Figure 6. This photo shows a 

variety of red colored maple leaves. 

To see this picture in color, visit 

http://www.scienceinvestigator.org.

Why do you think the scientists 

decided to collect leaf samples 

from June to October instead 

of from October to June?

Why is it important for the 

scientists to take a number of 

leaves from several trees and 

not just one or two?

This study was done in South 

Burlington, Vermont. Do you 

think late October would be the 

best time to view red leaves in 

Southern Georgia? (See figure 

7.) Why or why not?

Courtesy of Paula Murakami
14 The Investi-gator • http://www.scienceinvestigator.org 

Discussion

Collecting and studying the information 

about the leaves, air temperature, and day 

length helped scientists. It helped the 

scientists to understand when leaves were 

most likely to change color. This information 

is useful for the following reasons:

• This information is important for 

understanding a tree’s health. 

• This information is used each year to 

estimate dates when leaves will be 

changing color. 

• Tourists find this information helpful 

because it helps them plan their visits to 

forests. 

• It is also helpful to people in towns 

where tourists visit. Store owners and 

people who run hotels and gas stations 

use this information. They use it to plan 

supply orders. They also use it to 

schedule enough employees for the times 

when many tourists are visiting. 

As you can see, understanding when leaves 

will be changing color is good for a lot of 

people.

Understanding when fall leaf 

color is at its peak is good 

for a lot of people. What is 

one of the benefits for store 

owners?

Give another example of 

something seasonal that 

attracts tourists to an area.

If possible, think of an 

example from an area close 

to where you live.

Figure 7. 

Georgia is 

located closer 

to the equator 

than Vermont.

equator

Georgia

Vermont
The Investi-gator • http://www.scienceinvestigator.org 15

FACTivity

In this FACTivity, you will imagine what 

sugar maple trees in the northeastern United 

States might look like at four different times 

during the fall. To do this FACTivity, you 

will need four sheets of plain white paper and 

crayons or colored pencils. At the bottom of 

the first sheet, write “September 1.” On the 

bottom of the second, write “September 30.” 

On the bottom of the third, write “October 7.” 

On the bottom of the fourth, write “October 15.”

Take a large sheet of white paper and 

divide into four even sections. Label each 

section with each of the dates listed above. 

The pictures will be of either sugar maple 

leaves or trees. You can create a picture of 

just a few leaves or of an entire forest. Before 

coloring each picture, think about what you 

learned in this article. After you complete 

your pictures, share them with the class by 

posting them on the wall. What color were 

the leaves on each of the four dates? Why 

did you choose those colors? What was 

Useful Web Resources:

Starting in September, there is a Fall Color hotline on the Forest Service website where students 

can track fall leaf color change. http://www.fs.fed.us/

Environmental Education for Kids—Leaves

http://www.dnr.state.wi.us/org/caer/ce/eek/veg/trees/treestruecolor.htm

Science News for Kids—A Change in Leaf Color Article

http://www.sciencenewsforkids.org/articles/ 20060927/Feature1.asp

Maine’s Fall Foliage Video • http://www.maine.gov/doc/foliage/kids/movie.html

Nitrogen Cycle for Kids • http://www.eo.ucar.edu/kids/green/cycles7.htm

If you are a PLT-trained educator, you may 

use PLT Activity #42, “Sunlight and Shades 

of Green,” as an additional resource. 

happening to the leaf pigments on October 7? 

The students should compare their pictures 

and identify their similarities and differences.

Pigment is the material in cells and tissues 

that gives color to plants and animals. In this 

article, you learned about pigment in plant 

leaves. Humans have pigments, too. Look 

around your classroom and observe your 

classmates. As a class, identify three places 

that you can see where pigment affects a 

person’s color. Which of those might change 

color over a person’s lifetime?

FACTivity Extension
16 The Investi-gator • http://www.scienceinvestigator.org 

No LitteringO-Zone:

How Rising Ozone Levels Affect Tree Growth

Dr. Liu

Ecologist (E kôl o jist)

The great thing about being an ecologist 

is you are always on the way to 

discovering the secrets of nature. To 

answer a scientific question, you need 

to design an experiment, collect and 

interpret the experimental data, and 

then draw a conclusion. During those 

processes, I learn new knowledge. 

Most importantly, I can help keep our 

planet healthy by sharing my findings 

with other scientists and the public.

Dr. King

Forest Ecologist and Physiologist 

(Fiz e ôl o jist)

There are so many rewards to a career in 

science that it is difficult to pick a single 

favorite experience. The thing I like best 

about it is the ability to have an impact, 

that is, to do something good for people 

or the environment. Every time I publish 

a scientific paper or help a student to 

become a scientist, I feel that I help the 

world to be a better place. Also, I work 

on many different questions in many 

different places, so my work is always 

interesting! In the picture I am giving a 

talk to foresters in North Carolina. 

Meet the Scientists!
The Investi-gator • http://www.scienceinvestigator.org 17

Dr. Giardina

Forest Ecologist

My favorite science experience was traveling to the 

Central American country of Belize (beh lez) and 

wandering in a really cool and really big cave called 

the Rio Frio (re o fre o) cave near the western 

border with Guatemala (gwa tuh mal uh). The 

mouth of the cave is covered all around its rim with 

the most amazing trees. There were hundreds of 

types of giant trees. The roots of the trees were 

ringed all along the outside of the rim of the cave, 

and the cave was full of bats.

Meet the Scientists!
18 The Investi-gator • http://www.scienceinvestigator.org 

Figure 1. Look at the diagram of Earth’s 

atmosphere. What do you notice about the 

troposphere compared to the other layers? 

Thinking About 

Science

Scientists want to 

discover the correct 

information about our world. 

To do this, they often set 

up experiments. They want 

these experiments to be as 

close to the real world as 

possible. In this study, the 

scientists wanted to know 

how increasing the amount 

of ozone (o zon) might affect some types of 

trees. You will learn about ozone in the next 

section. 

One way to find out how ozone affects 

trees might be to put potted trees into a room. 

Then the scientists could increase the amount 

of ozone in the room. Does this seem like the 

real world to you? It did not seem that way 

to the scientists either! Instead, the scientists 

planted trees outside in a special area. They 

constructed towers that released ozone into 

the wind. The wind carried the ozone to the 

trees. This allowed scientists to observe how 

the trees respond to ozone in a more natural 

environment.

Thinking About the 

Environment

Have you heard about the 

chemical ozone? Ozone is 

a gas that contains 

oxygen. Ozone 

is found in the 

atmosphere. Sometimes ozone can be helpful 

and sometimes it is harmful. 

The atmosphere has different layers 

(figure 1). The troposphere (trop o sfer)

is the layer of atmosphere closest to Earth

Thermosphere

80–320+ km

0–12 km Troposphere

12–50 km Stratosphere

50–80 km Mesosphere
The Investi-gator • http://www.scienceinvestigator.org 19

Figure 2. This is a picture of Earth’s 

atmosphere from space. The atmosphere 

is the light colored band. Sally Ride, the 

first woman in space, took this picture. 

Photo is courtesy of NASA.

Figure 3. This diagram shows you how fossil fuels are made. Do you think this 

process is quick or slow? Why?

(figure 2). When ozone is found in the 

troposphere, it is harmful. Ozone is the 

main ingredient of smog (smawg). Smog is 

polluted air and is a danger to human health. 

Ozone is also found in the stratosphere 

(strat o sfer). The stratosphere is a higher 

level of the atmosphere (see figure 1). In 

the stratosphere, ozone provides a layer 

of protection from the sun’s harmful rays. 

This example shows how ozone can also be 

helpful.

You can see that ozone can both protect 

and harm life on Earth. Humans can create 

more ozone. For example, fossil fuels (fôs

ul fyools) are fuels that are formed from the 

remains of animals from the past (figure 3). 

Gasoline is an example of a fossil fuel. When 

people burn fossil fuels, the amount of ozone 

in the troposphere rises. The increase in 

ozone impacts humans as well as other living 

things. The scientists in this study wanted to 

know how trees might be affected by rising 

levels of ozone in the troposphere.

Pronunciation Guide

Accented syllables are in bold.

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

OCEAN

300–400 Million years ago

OCEAN

50–100 Million years ago

Sand and Silt

Plant and Animal Remains

Sand, Silt and Rock

Oil and Gas Deposits

Tiny sea plants and animals died 

and were buried on the ocean 

floor. Over time, they were covered 

by layers of silt and sand.

Over millions of years, the remains 

were buried deeper and deeper. The 

enormous heat and pressure turned 

them into oil and gas.

Today, we drill down through layers 

of sand, silt, and rock to reach the 

rock formations that contain oil and 

gas deposits

adapted from U.S. Department of Energy
20 The Investi-gator • http://www.scienceinvestigator.org 

Introduction

Every fall, deciduous (de sij oo us) 

trees drop their leaves to the forest floor. 

Deciduous trees are trees that lose their leaves 

in the fall or winter. These fallen leaves are 

called leaf litter (lef lit ür) (figure 4). After a 

while, the fallen leaves begin to break down. 

When leaf litter breaks down, it provides 

nutrients (noo tre ents) for the soil (figure 5). 

Nutrients are any substance found in foods 

that are necessary for plants and animals. This 

movement of nutrients from leaves to the 

soil is important. It helps new plants grow. 

Two of the main nutrients from fallen leaves 

are carbon and nitrogen. These nutrients 

are important to continue the cycle of plant 

growth on Earth.

Nutrients that go into the soil are affected 

by two things. First, the number of leaves that 

grow every season is important. Second, what 

the leaves are made of is important, too. If 

something happens to change the number of 

leaves on trees or their makeup, the soil might 

be changed as well. 

 In recent years, humans have been 

burning more and more fossil fuels. Fossil 

fuels are oil, natural gas, and coal. One of the 

extra products created by burning fossil fuels 

is ozone. Since the level of ozone is rising, 

the scientists wanted to know how this affects 

how trees grow. Tree growth starts in leaves. 

Therefore, scientists started by looking at the 

leaves. They looked at how many leaves were 

produced. They also looked at the amount of 

nutrients in the leaves. 

Figure 4. This is a picture of leaf litter. 

What do you notice about it?

Figure 5. Leaves have fallen 

around this plant. The leaf litter 

provides nutrients and protection 

for the plant. 
The Investi-gator • http://www.scienceinvestigator.org 21

In your own words and in the 

form of a question, state what 

the scientists wanted to learn.

Think about trees growing 

inside a building and trees 

growing outside. Name three 

things that make observing 

trees outside more natural 

than observing them inside.

Figure 8. Notice how the tops of trees 

are touching in this tree canopy.

Figure 6. Rhinelander, Wisconsin 

is located in the northern portion of 

Wisconsin.

Figure 7a and 7b. Aspen (7a) and 

birch (7b) leaves.

7a 7b

Method 

The study took place near Rhinelander, 

Wisconsin (figure 6). The scientists divided 

a large area of land into three blocks. In each 

block, they planted small areas with aspen 

and birch trees. These trees are fast-growing 

(figures 7a and 7b). The scientists waited 

until the trees were six years old to take their 

measurements. They did this because they 

wanted information about older trees where 

the tops of the trees are touching (figure 8). 

In one area, the scientists did not spray 

ozone gas into the trees. The scientists used 

this area as a control (kän trol). A control 

is something used for comparison when 

checking the results of an experiment. In 

this experiment, the control is an area where 

no ozone is sprayed. In the second area, the 
22 The Investi-gator • http://www.scienceinvestigator.org 

scientists sprayed ozone gas into the trees 

(figures 9 and 10). The scientists sprayed 

these trees for six years until it was time to 

measure them. 

The scientists placed baskets under the trees 

in each of the areas. Baskets were placed in a 

circle in the middle of the trees. The baskets 

were evenly spaced. The baskets caught leaf 

litter falling from the trees. The contents of the 

baskets were collected every two weeks. This 

continued from June through October until all 

leaves had fallen off the trees. 

After collecting the leaf litter, the scientists 

dried it. Drying it removed any moisture. The 

scientists weighed the dried litter. This helped 

the scientists determine how much living 

material was in the leaf litter and how much 

leaf litter was produced. 

Next, the type and amount of nutrients in 

the leaf litter were measured. This helped 

scientists know how ozone affected the 

Figure 10. This is a close up photo 

that shows the circle of trees with 

the ozone sprayers. 

leaves. Finally, the scientists compared the 

measurements of leaves collected from trees 

that had not been sprayed with ozone gas with 

leaves from trees that had been sprayed with 

ozone gas.

Figure 9. This photo shows the 

experimental site. The sprayers can 

be seen as small ovals in this photo. 

These sprayers sprayed ozone into 

the wind. The wind carried the 

ozone to the trees.

When people rake leaves in 

the fall, they take nutrients 

away that could one day 

become a part of the soil. 

What do people do to their 

lawns to make up for this?

Do you think scientists must 

have patience to do some 

of their experiments? What 

evidence of this can you find 

in the “Method” section?
The Investi-gator • http://www.scienceinvestigator.org 23

If the scientists collected the leaf 

litter every two weeks from the 

beginning of June until the end of 

October, how many times in all 

did they collect the leaf litter?

Based on the findings, do 

you think that higher levels 

of ozone would be good 

for trees and other plants 

growing in the forest? Why or 

why not?

If less leaf litter is produced, 

would growing plants be 

helped or hurt? Explain your 

answer.

Discussion

In areas with higher ozone, the way leaves 

were made caused the leaf litter to break down 

more slowly. Additionally, smaller amounts 

of leaf litter were produced. Therefore, there 

were fewer nutrients available to growing 

plants. The leaf litter also contained less 

carbon and nitrogen. These nutrients are 

important for the plant growth cycle. Findings

The scientists compared the trees sprayed 

with ozone to the trees growing under normal 

conditions. Trees growing in higher levels of 

ozone had lower levels of living material in 

their leaf litter. Overall, the amount of carbon 

and nitrogen was lower in leaf litter from trees 

grown in higher ozone levels. In addition, the 

trees also had fewer leaves.

Based on the findings and 

discussion in this study, do 

you think humans should 

try to reduce the amount of 

ozone being produced? Why 

or why not?

What is the answer to the 

scientists’ question? Reread 

the end of the “Introduction” 

if you have forgotten the 

scientists’ question.
24 The Investi-gator • http://www.scienceinvestigator.org 

The method you will use to do this is:

The class will divide into groups of four 

students. One half of each group will study 

the impact of ozone that occurs close to Earth, 

in the troposphere. The other half will study 

the impact of ozone that occurs in the upper 

atmosphere, in the stratosphere. You can 

do your research in the library and on the 

internet. 

Gather information about the effects of 

ozone, and how human activities are affecting 

ozone. After each team of two students has 

collected their information, the team should 

summarize the information about ozone. 

In the summary, include information about 

where the ozone occurs. Each group of four 

students should then share and compare 

the summarized information within their 

group. As a group, discuss how ozone 

is both beneficial and harmful. Compare 

ozone’s benefit and harm with where the 

ozone is found in each situation. Develop 

recommendations about what people can do 

in relation to ozone in the troposphere and in 

the stratosphere. Document your learning by 

creating a poster, which you will share with 

the class.

Hold a class discussion about what 

each group learned about ozone. Compare 

ozone in the troposphere with ozone in the 

stratosphere. What are the differences and 

similarities? 

Useful Web Resources:

EPA’s Sunwise Kids Ozone Layer information

http://www.epa.gov/sunwise/kids/kids_ozone.html

National Geographic for Kids Ozone Article

http://kids.nationalgeographic.com/Stories/SpaceScience/Ozone

Environmental Education For Kids—Ozone Layer

http://www.dnr.state.wi.us/Org/caer/ce/eek/earth/air/ozonlayr.htm

FACTivity

Stratospheric ozone team

Stratospheric ozone

Ozone UV radiation

Tropospheric ozone team

Tropospheric ozone

Ozone pollution

The question you will explore in this FACTivity is:

How does ozone in the troposphere and stratosphere impact Earth? 

Some search terms each team might use:

If you are a PLT-trained educator, you 

may use PLT Activity #73, “Waste 

Watchers,” as an additional resource.
The Investi-gator • http://www.scienceinvestigator.org 25

Out of the Penalty Box

Protecting the Environment Through Policies

Meet the scientists!

Dr. Bengston

Research Forester

My favorite science experience was 

learning about urban growth and urban 

policies in South Korea. I learned about 

them when I was a visiting scientist at 

Seoul (Sôl) National University during 

the summer of 2004. Managing urban 

growth is important. It was exciting to see 

the effects of Korea’s policies (päl uh 

ses) to manage urban growth and protect 

the environment. Policies are like rules 

we must follow. A highlight was hiking 

the heavily used recreational trails that 

surround Seoul. Seoul is an urban area 

of more than 20 million people (which is 

more than twice the population of New 

York City!). 

My favorite science experience was 

working with Mayan (mi yun) farmers and 

scientists to solve problems in Chiapas

(che op us), Mexico. We worked on 

several projects. In one community, we 

worked on projects with trees to reduce 

global warming. In other communities, we 

discovered how to provide good soil for 

growing coffee. We also discovered how 

to provide habitat (hab uh tat) for migratory

(mi gruh tôr e) birds. Habitat includes the 

physical things that plants and animals 

need to survive. Migratory birds are birds 

that move from place to place for breeding 

or feeding. Finally, in another community 

we examined what happened when 

crocodiles and fishermen wanted to be in 

the same place in the forests and estuaries

(es chu air es). Estuaries are places where 

the ocean tide meets a river current. 

Dr. Nelson

Environmental 

Sociologist
Figure 1. Scientists use books, the 

Internet, and many other sources for their 

research.

Figures 2a and 2b. These two photos 

show urban growth. Have you seen 

urban growth where you live?

2a

Thinking About 

Science

Scientists learn as 

much as possible about 

their topic. They research 

the Internet, libraries, and other 

sources (figure 1). They do this 

to discover what other scientists 

have found out. Once they 

have found the information, 

they have to understand it. To 

do this, scientists compare and 

contrast what they have found. Then they 

summarize the information in one document. 

You do this very thing when you prepare a 

paper for class. When scientists do this, it tells 

them two things. These things are: 1) what 

information is already known about a topic, 

and 2) what information is not known. Once 

they have learned as much as possible, they 

move forward with their own research. 

Thinking About 

the Environment

The United States 

population is increasing. 

This increase causes 

changes in the 

environment. 

As a society, 

we pass laws 

and make policies (päl uh ses) to manage 

these changes. Many of the policies and 

laws help to keep the environment healthy. 

Policies are like rules we must follow. 

Environmental policies can do two things to 

reduce unwanted changes in the environment. 

Policies can either manage urban growth

(ür bun groth) or protect open space (figures 

2 and 3). Urban growth is the growth of a 

city. This growth is caused by an increasing 

population. 

2b

26 The Investi-gator • http://www.scienceinvestigator.org 
Figures 3a and 3b. Open spaces are areas in your community that are not highly 

developed areas. Examples of open areas are parks and pastures. 

3b

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

3a

The Investi-gator • http://www.scienceinvestigator.org 27
28 The Investi-gator • http://www.scienceinvestigator.org 

that have been used to manage urban growth 

and protect open space? The second question 

is: Which of these types of policies has been 

most effective?

Environmental policies either 

use penalties or rewards to 

achieve their objectives. Think 

of two policies that you must 

follow at home or school, one 

based on penalties and the 

other based on rewards. 

Think about whether you 

would follow the policy without 

the penalty or the reward. 

Is one type of policy more 

effective than the other or are 

they equally effective? Why 

or why not? You must think 

beyond whether you like the 

policy. 

What are the questions the 

scientists wanted to answer in 

this study? 

Introduction

Over the next 25 to 45 years, scientists 

think the Nation’s population will double. As 

the population increases, cities, suburbs, and 

towns use more and more land. In order to 

keep some open space, the government makes 

environmental policies that everyone must 

follow. 

These policies fall into three types. The 

policies either punish people or reward 

people for following the policy. The first 

type of policy limits or controls urban 

growth. Penalties are placed on people 

or organizations when they do not follow 

the rules. Penalties are used to protect the 

environment. In the second type, policies 

reward people or organizations for doing 

things to limit urban growth or protect 

open space. Rewards are used to protect 

the environment. In the third category, the 

government owns and takes care of the land.

Most of these policies are made by local 

governments. Some examples of local 

governments are cities, counties, townships, 

or parishes. State and federal governments 

also make environmental policies. Not 

much is known about how successful these 

policies have been in managing urban growth 

and protecting open space. This question is 

important. It is important because if society 

wants to reduce unwanted changes in the 

environment, we need to know which types of 

policies are most effective. 

The scientists in this study wanted to 

answer two questions. The first question is: 

What are the characteristics of the policies 
The Investi-gator • http://www.scienceinvestigator.org 29

22-12=

Method

The scientists did their research. They 

looked for documents that described 

environmental policies. They read science 

journals, books, government reports, and 

web sites. They found many environmental 

policies. In fact, they found so many policies 

that they had to figure out which ones to use. 

They had to set criteria (kri ter e uh) 

for what they would include in their study. 

Criteria are standards or measures that are 

used in making a decision. They came 

up with three criteria. The scientists only 

included policies made after 1980. Second, 

the policies had to be made in the United 

States. Third, these policies had to be made 

by local, state, or federal governments. 

When the scientists found a policy that fit 

their criteria, they placed it into one of three 

policy types. Two of those policy types are 

described in the “Introduction” section above. 

The third type was for any land purchased or 

managed by a government on behalf of the 

public (figure 4).

Figure 4. The three types of 

environmental policies are shown below.

l Policies that use penalties.

l Policies that use rewards.

l Policies that call for buying and 

managing land for public use, such 

as public parks, forests, and 

recreation areas.

If a policy was made in 1981, how 

many years old would the policy 

be today? 

The scientists then studied the policies 

in each of the three policy types. They took 

notes on each policy. Then they compared 

the policies by looking for similarities and 

differences. Some of the policies had been 

evaluated (e val u ated) to see if they were 

effective or ineffective. Evaluated means 

examined and judged carefully. The scientists 

took notes on why the policy was judged to be 

effective or ineffective.
30 The Investi-gator • http://www.scienceinvestigator.org 

Name at least two of the 

criteria used by the scientists 

to select which environmental 

policies to study. 

Think about the last time you 

chose to buy something. This 

could be a piece of clothing, a 

CD, or any other item. Name 

two criteria that you used 

when you decided which item 

to buy. 

Examine figure 4. The third 

type of environmental policy is 

land that is or was purchased 

by a government and 

managed for the benefit of the 

public. Name one area in your 

community that would fit into 

that policy type.

Findings

The scientists found 87 documents that fit 

their criteria. Examples for each of the policy 

types are shown in figure 5.

The scientists looked to see what policies 

had been evaluated. The scientists found 

that not many of the policies had been 

evaluated. Therefore, it was difficult to 

figure out which types of policies were most 

effective. Although the scientists did not find 

much information, the scientists drew these 

conclusions from studying the policies:

A policy was more effective if:

1. The land area it affected was clearly 

identified.

2. Someone kept a close check on 

whether the policy was being 

followed.

3. Any required paperwork was easy to 

fill out.

4. The policy was started quickly.

The scientists also discovered that it was 

better to use several policies at one time. The 

use of several policies protected more open 

space and limited urban growth better. For 

example, using a combination of the policies 

from figure 5 would bring more success than 

just using one. 

Finally, the scientists found that 

communication is important. Policies were 

more successful when the policies were 

discussed with the people they would affect. 
The Investi-gator • http://www.scienceinvestigator.org 31

Managing urban growth

Public ownership of 

parks, recreation areas, 

forests, wildlife areas, 

wilderness areas to 

manage urban growth

Placing an upper limit 

on the number of new 

buildings allowed to be 

built every year 

Lowering taxes for new 

businesses to take over 

existing but unused 

buildings, rather than 

building new buildings

Protecting open space

Public ownership of 

parks, recreation areas, 

forests, wildlife areas, 

wilderness areas to 

protect open space

Requiring developers 

to set aside some open 

space for every new 

home constructed in a 

subdivision

Lowering taxes on land 

that is to be kept as open 

space

Types of policies

Government 

purchase and 

management of 

land

Control and 

punishment

Reward

Figure 5. Examples of each type of 

environmental policy are listed below.

Goal of policies
32 The Investi-gator • http://www.scienceinvestigator.org 

Look at the list of four 

reasons a policy was more 

effective. Which of the four 

applies most to the policies 

that you must follow at 

home? 

In most communities, people 

can be fined if they throw 

litter on the ground. Into 

which row and column in 

figure 5 would you place 

this policy? Why would you 

place it there?

Discussion

Based on this research, the scientists 

decided several things. The scientists decided 

that citizens should be involved in making 

policies for the environment. Citizens should 

also be involved in putting them into practice. 

Better communication would make policies 

for the environment more successful. As the 

Nation’s population continues to grow, we 

must find ways to manage urban growth and 

protect open space. 

Think about the conclusions of 

the scientists, outlined in the 

“Discussion” section, above. 

Based on these conclusions, 

what is one important aspect 

of implementing a successful 

policy? 

Do you think it is important 

to manage urban growth and 

protect open space? Why or 

why not?
The Investi-gator • http://www.scienceinvestigator.org 33

In pairs or in groups, identify five policies that exist in your school. Complete the following 

chart for each policy you choose.

Name or 

description of 

the policy

What is the goal 

of the policy?

Who developed 

the policy?

Who 

implements the 

policy?

Does the policy 

use rewards or 

penalties?

Whose support 

is needed for 

the policy to 

succeed?

How does the 

school identify 

if the policy is 

succeeding?

Who or what 

benefits from 

the policy?

How could 

the policy be 

improved?

The Investi-gator • www.scienceinvestigator.org 33

Policy 1 Policy 2 Policy 3 Policy 4 Policy 5
34 The Investi-gator • http://www.scienceinvestigator.org 

After all groups have completed their figures 

for the policies, hold a class discussion about 

the policies. Use these questions to get started:

1. How many different policies were 

identified?

2. As a class, place the policies into different 

categories. Categories can be made up by the 

students. Some examples include hallway 

behavior, classroom behavior, lunch room 

procedure, and policies to keep people safe. 

3. What categories did you develop?

Useful Web Resources:

NASA’s Urban Sprawl 

http://science.nasa.gov/headlines/y2002/11oct_sprawl.htm

Kids and Community—Learn about an Urban Planner!

http://www.planning.org/kidsandcommunity/

continued

FACTivity Extension

Identify policies in your school that are 

specifically intended to protect the school’s 

natural environment. Complete the same table 

on page 33 for these policies.

If there are no policies specifically 

intended to protect the school’s natural 

environment, then your groups will begin 

to develop some policies. In your groups, 

develop two new policies aimed at improving 

the school’s natural environment. Fill 

out the table on page 33 for your new 

policies. Develop a plan to get the policies 

implemented. Some examples to get you 

started include:

4. What do you think, overall, is the goal of 

these policies?

5. Which policies are effective?

6. Why are the policies effective or not 

effective?

If you are a PLT trained educator, you may use PLT 

Activity #55, “Planning the Ideal Community”, Activity 

#56, “We Can Work It Out”, Activity #58, “There 

Ought to be a Law,” as an additional activity resource.

l No littering on school grounds.

l Recycle paper, cans, and plastic within 

the school.

l Use only recycled paper.

l Increase the use of computers.

l Plant five trees every year on school 

grounds.

l Develop and maintain a wildflower garden 

on school grounds.

l Develop and maintain a small pond on 

school grounds.

l Support bird life with bird houses and bird 

baths on school grounds.

l Reduce the use of pesticides and herbicides 

on school grounds.
The Investi-gator • http://www.scienceinvestigator.org 35

Dr. Campbell

My favorite science experience 

was seeing the aurora (uh rôr

uh) borealis (bôr e al is) (northern 

lights) while hiking back from a 

long day of fieldwork in Adirondack 

Mountains in New York.

Dr. Mitchell

I am most interested in understanding 

how climate change is affecting 

watersheds (wä tür sheds). A watershed 

is an area of land from which all of the 

water drains into one stream or river. 

Specifically, I am interested in watersheds 

with forests during the winter. This work 

has included efforts at various sites in 

the northeast United States including 

Hubbard Brook Experimental Forest and 

Huntington Forest. I am also studying 

the effect of climate change in East Asia. 

Most recently, I have been working on 

a project at Lake Hovsgol in northern 

Mongolia. 

The picture shows me at Lake Hovsgol 

in summer 2008 where I was doing field 

work related to watersheds.

Snowed In?

A Closer Look at Soil Activity in the Wintertime
36 The Investi-gator • http://www.scienceinvestigator.org 

Dr. Christenson

It is difficult to pick just one experience; 

science can be really fun (most of the 

time!). So if I have to choose just one, 

it would be tracking moose through the 

snow to find their fresh droppings! I 

collect the ‘moose poop’ then analyze 

it for a number of elements back in the 

laboratory. This allows me to better 

understand how moose interact with their 

habitat (hab uh tat). A moose’s habitat is 

the natural area in which it lives.

Dr. Groffman

My favorite science experience was 

when we looked at the chemical results 

from our field experiments. We saw 

that our experiment had worked and 

that our hypotheses (hi poth uh ses) 

about the effects of winter climate 

change were correct. A hypothesis is 

an unproven idea. With a complicated 

field experiment, so many things have 

to be done exactly right to get scientific 

results. It’s great fun when it all 

happens the way it is supposed to!
The Investi-gator • http://www.scienceinvestigator.org 37

Figure 1. This map shows some of the 

states that are in the northeastern United 

States. The states shown are Maine, New 

Hampshire, Vermont, Massachusetts, 

Rhode Island, Connecticut, New York, 

New Jersey, and Pennsylvania.

Thinking About 

Science

Scientists discover new 

information. This new 

information affects the 

work of other scientists. Can 

you guess why this is so? 

New information creates new 

scientific questions. In this 

study, evidence of a changing 

climate caused scientists to 

ask questions they had never 

asked before. 

Wintertime in the northeastern United 

States (figure 1) seems like a time when 

everything slows down. Scientists thought 

this was also true of some natural processes

Figure 2. The soil may look dead, but it 

is full of living things!

(na cha rôl prä ses es). Natural processes are 

things that happen naturally in nature, such 

as tree growth and rainfall. The reports of 

warming temperatures caused scientists to 

start thinking about wintertime. 

They wondered how rising temperatures 

would affect wintertime natural processes. 

Scientists thought about this question a lot. 

They also read work of other scientists to 

see what other scientists thought about the 

question. 

Thinking About the 

Environment

Do you ever wonder what 

happens under 

the ground? Is 

the soil just 

dirt? (figure 2). Is it a home for plants and 

animals? Although soil often looks like it 

Courtesy of evgschool.org
38 The Investi-gator • http://www.scienceinvestigator.org 

is just dirt, it is a busy place! For example, 

earthworms live in the soil. You probably 

know about earthworms, but there are other

organisms (ôr gä niz ums) in the soil. An 

organism is any living thing. 

Did you know that tiny organisms, called 

microbes (mi krobz), live in the soil? Most 

microbes are too small to see with your 

eye alone. Microbes include algae, plants, 

bacteria, and other animals. One gram of soil 

contains millions of these small individual 

organisms! One gram of soil is about 

the weight of a paper clip. Some of these 

organisms eat material that is naturally in the 

soil. Others eat the waste products of other 

organisms. Although you cannot see microbes 

at work, their activity creates the soil. All life 

depends upon this soil. What are two ways 

that people depend on soil? 

Figure 3. Alpine areas are 

found in high mountains, where 

there are few or no trees.

Figure 4. Arctic areas are 

found in the far north, where 

winters are long and the 

ground stays frozen most of 

the year.

Introduction

Scientists have done research on soil 

during the winter. Much of this research has 

happened in alpine (al pin) and arctic (ark

tik) areas. Alpine areas are found in high 

mountains, where there are few or no trees. 

Arctic areas are found in the far north, where 

winters are long and the ground stays frozen 

most of the year. In these areas there is little 

tree cover and winters are long 

(figures 3 and 4).

In the past, scientists did not spend 

much time studying wintertime soil in the 
The Investi-gator • http://www.scienceinvestigator.org 39

Scientists believe that Earth’s climate is 

getting warmer. If the climate continues to 

get warmer, then there could be more cycles 

of freezing and thawing. The scientists 

wondered what would happen to the microbes 

in the soil if there were more cycles of 

freezing and thawing. By studying other 

scientists’ research, the scientists found that 

some scientists had already tested the impact 

of thawing and freezing on soil. 

When these scientists did their study, they 

first tested it in a laboratory (lab ra tôr e)

setting (figure 6). A laboratory setting is 

usually inside a building where conditions 

may not be the exact same as conditions 

outside. It is a more controlled environment 

than a natural environment. In a laboratory 

Figure 5. Snow-covered ground protects 

the soil from freezing.

northeastern United States. The reason they 

did not study the soil is because they thought 

the cold temperatures caused most of the 

activity of living things in the soil to stop. 

However, the changing climate made the 

scientists stop and think. Scientists began to 

wonder what would happen if climate change 

caused rising wintertime temperatures.

By studying other scientists’ research, the 

scientists learned a lot. They found out that 

during the winter in alpine and arctic areas, 

many natural processes do not stop. The 

soil, in particular, is a busy place even during 

the winter. When snow covers the ground, 

it protects the ground from freezing (figure 

5). This allows many of the soil activities to 

continue during the winter. If this is true for 

soil in the northeastern United States, then 

snow-covered ground provides an important 

ecological (e ko law juh kul) benefit to 

the plants and animals who live there. An 

ecological benefit means that there is a good 

relationship between the organism and the 

environment. 

Figure 6. This is a picture of 

a Forest Service scientist’s 

laboratory. Can you name some 

ways this setting is different than 

an outdoor setting?
40 The Investi-gator • http://www.scienceinvestigator.org 

setting, things like temperature and lighting 

can all be easily controlled. In the laboratory 

setting, the scientists found that freezing and 

thawing increases the activity of microbes. 

Scientists think that some of the microbes 

may die when the soil freezes and then the 

microbes that are left eat the dead ones to 

survive. The scientists wanted to know what 

happens to the activity of microbes if the 

freezing and thawing cycle happens in the 

natural environment instead of a laboratory 

setting. 

Wyoming

Colorado

New 

Mexico

Pacific 

Ocean

Method

The scientists read the research of other 

scientists. Some of this research had been 

done in other places with cold winters. Two 

of the places researched were Colorado 

(figure 7) and Canada. Colorado has cold 

winters in the mountainous areas of the State 

(figure 8). Canada’s winters are cold because 

Canada is far from the equator (figure 9). The 

scientists also read about research done in the 

northeastern United States.

Figure 8. Can you guess what 

time of year it is in the Rocky 

Mountains of Colorado? 

Figure 7.

Colorado is 

located in the 

western United 

States.

What question did the 

scientists want to answer? 

If soil that never froze before 

began to freeze during the 

winter, do you think soil activity 

would be affected? If so, how 

do you think soil activity might 

be affected? 

Fig. 8 courtesy of Reghan and John Cloudman, Canyon Lakes Ranger District

Adapted from www.lib.utexas.edu
The Investi-gator • http://www.scienceinvestigator.org 41

Figure 9. Canada is located far from the 

equator, where the climate is warm.

Figure 10. Snow was shoveled from an 

area in the Hubbard Brook Experimental 

Forest in New Hampshire to observe the 

effect of changing temperatures on winter 

soils. 

Do you think that wintertime 

soil activity in the northeastern 

United States is similar to 

wintertime soil activity in 

Canada? Why or why not?

Do you think the scientists 

should have read about 

research done on wintertime 

soil activity near the equator? 

Why or why not? 

In this study, the scientists wanted to see 

what would happen to the activity of microbes 

when the freezing and thawing happened in a 

natural setting. To do this, scientists caused 

the soil to freeze outside by removing the top 

layer of snow during the winter (figure 10).

Adapted from http://chuma.cas.usf.edu/~juster/volc1/world%20map.gif
42 The Investi-gator • http://www.scienceinvestigator.org 

Discussion

Scientists do not know a lot about soil 

activity during the winter in the northeastern 

United States. However, they know that plants 

and animals are more active during the winter 

Figure 11. A compost pile contains 

leaves and other waste products. If you 

put a thermometer in a compost pile, you 

would be able to see the temperature is 

warmer because of the heat generated by 

the soil microbes. 

Findings

Do you remember that microbes live in 

the soil? These microbes are quite busy. 

They produce heat when they are active in 

the soil (figure 11). This heat causes the soil 

temperature to rise. This heat helps to keep 

the soil warm throughout the winter. When 

snow falls and the temperatures are cold, 

the snow stays on the ground throughout the 

winter. The snow insulates (in suh lats) the 

ground. Insulation keeps the area warmer. 

The warm ground enables the microbes to 

continue their activity. 

The scientists found that the freezing 

and thawing cycle in a natural setting did 

not cause microbe activity to increase. This 

finding was quite different than what the 

scientists in the laboratory setting found. 

Do you remember what they found in the 

laboratory setting?

Does the human body 

produce heat as a result of 

activity? How do you know? 

Restate in your own 

words what the scientists 

discovered. 

Why do you think the 

scientists had two different 

findings depending on 

whether they did their 

research in a laboratory 

setting or a natural setting? 
The Investi-gator • http://www.scienceinvestigator.org 43

than previously believed. From this study, the 

scientists learned that in a natural setting there 

was a different outcome than in a laboratory 

setting. In the natural setting, the scientists 

found that when soil was frozen, microbe 

activity did not increase. However, in the 

laboratory setting, scientists found that soil 

microbe activity increased. Scientists think 

that it may not have gotten as cold outside as 

it did in the laboratory setting and therefore 

they got different results.

 This study shows why it is important to 

conduct a scientific study in an area that is 

as similar as possible to the environment the 

scientist is interested in studying. This study 

also shows why it is important that studies are 

repeated several times by different scientists 

before any conclusions are made. 

If you were the scientist, how 

would you explore whether 

higher average temperatures 

affect soil activity over the 

entire winter? 

Why do you think scientists 

first tested soil microbe activity 

in a laboratory setting?

Soil Investi-gators

In this FACTivity, students will 

investigate the soil in their school yard and 

some soil from home. You will need at 

least five empty plastic bins, five small hand 

trowels, magnifying lens, plastic spoons, 

plastic sandwich bags, permanent markers, 

rulers, plastic containers or sinks with water, 

and science journals. 

Divide students into small groups of three 

or four students. Give each group a plastic 

bin and a hand trowel. Take students outside 

to collect two samples of the soil. Before 

students collect samples of soil, have student 

note-takers write down a description of the 

area from which each soil sample will be 

taken. The soil sample from the student’s 

neighborhood should be brought back with the 

student the next day.

After each group has collected its soil 

samples, bring the samples to an area where 

students can sift through the soil and make 

notes about what they find in their soil sample. 

Students will use the chart provided to make 

their notes. 

Student Procedure:

1. Using your spoon and plastic bags, you 

will collect three different looking types of 

soil to investigate. Choose at least one from 

your neighborhood and two from the school 

grounds. The one from your neighborhood 

should be brought back with you tomorrow. 

Be sure to label the plastic bag with 

information about where you collected the soil. 
Useful Web Links:

To learn more about soil microbes, visit 

http://rivenrock.com/soilmircrobes.htm. 

Underground Virtual Adventure—

The Field Museum

http://www.fieldmuseum.org/underground 

adventure/virtual_tour/index.shtml#

Discovery Education Soil Safari

http://school.discoveryeducation.com/

schooladventures/soil/soil_safari.html

Bureau of Land Management Just For 

Kids Soil Biological Communities

http://www.blm.gov/nstc/soil/Kids/soilcrus.html

From: Campbell, J. L., Mitchell, M. J., Groffman, P. M., 

Christenson, L. M., and Hardy, J. P. (2005). Winter in 

northeastern North America: A critical period for ecological 

processes. Frontiers in Ecology and Environment, 3(6): 314-322,

http://www.treesearch.fs.fed.us/ubs/21274 

If you are a PLT-trained educator, you may use PLT Activity 

#24, “Nature’s Recyclers,” as an additional resource. 

2. Complete the chart above.

3. After students have filled in their charts 

and had time to examine the soil, have a class 

discussion about the different types of soil 

the students found. As a class, you can create 

a soil chart of the different soils that were 

found. 

*This FACTivity was adapted from “Scoop, 

There it is!” by Todd R. Nickelsen.

Where did you collect this sample?

Describe the sample site (i.e., sunny, 

moist, dry, shaded, forested-you don’t 

have to use these terms)

How deep did you dig to get your 

sample?

What color is the sample?

What does the sample smell like?

What does the sample feel like?

Is there any evidence of living or dead 

plants or animals? Describe.

Does the sample contain iron? How 

could you check?

Describe the particles. What about 

their size? Shape? Color? 

Observations Sample 1 Sample 2 Sample 3

44 The Investi-gator • http://www.scienceinvestigator.org 
The Investi-gator • http://www.scienceinvestigator.org 45
46 The Investi-gator • http://www.scienceinvestigator.org 
The Investi-gator • http://www.scienceinvestigator.org 47
48 The Investi-gator • http://www.scienceinvestigator.org 

The Investi-gator is a member of the Natural Inquirer family. The Natural Inquirer is a science education 

journal for middle school students. To explore more resources for using these journals, visit the Natural 

Inquirer Web site at http://www.naturalinquirer.org

Dr. Barbara (Babs) McDonald

Forest Service

320 Green St.

Athens, GA 30602-2044

706-559-4224

bmcdonald@fs.fed.us 

In subject line, please put: Educator feedback

Visit these web sites for other useful information:

U.S. Forest Conservation Education

http://fs.usda.gov/conservationeducation

Cradle of Forestry

http://www.cradleofforestry.com

Note to Educators

Science education is increasingly in the spotlight as 

society recognizes the importance of scientific literacy to 

the Nation’s future. As teachers of science, you are being 

asked to prepare your students by providing both breadth 

and depth in science topics and process. The Investi-gator 

is a resource to help you teach both scientific content and 

process to your students. The Investi-gator integrates 

science with a number of disciplines, including language 

arts, geography, math, and social studies. Therefore, the 

Investi-gator can be used for team teaching or simply 

to reinforce the interdependent nature of learning and 

knowledge to your students.

You understand the importance of hands-on learning. 

While hands-on experience is a critical component of 

student scientific learning, science education standards 

have increasingly also highlighted the role of minds-on 

learning. True scientific literacy occurs when students 

can critically think about scientific questions, processes, 

and findings, as well as participate in data collection, 

observation, and analysis. You can use the Investi-gator

to introduce science as a process that integrates minds-on 

learning with hands-on learning. At the end of each article, 

an easy-to-do activity, called a FACTivity, is provided 

to highlight a topic or process concept from the article. 

A reference to appropriate Project Learning Tree (PLT) 

activities are also provided for those educators certified in 

PLT. For more information about PLT, visit http://www.

plt.org. 

How To Use This Journal In Your Classroom

The Investi-gator is written at the fifth grade level. 

Each article is written from an actual published scientific 

paper presenting contemporary environmental research. 

At the back of this journal, you will find two resources 

to help you use the journal more effectively. A matrix is 

given which indicates which national science education 

standards can be addressed by each article. A lesson 

plan is also provided that can be used with all four of the 

articles. The lesson plan helps you apply a reading strategy 

that will increase student comprehension. Along with the 

FACTivity, the lesson plan will help you integrate mindson and hands-on scientific learning.

Help Us Improve the Investi-gator 

On pages 52 and 53 of this journal and on http://www.

naturalinquirer.org, you will find student and teacher 

evaluation forms. These forms give you an opportunity 

to provide feedback that will help us improve the journal. 

Please take a moment to complete the evaluation form and 

if possible, invite your students to evaluate the journal as 

well. By completing the evaluation form, your students 

can learn the importance of providing assessment, much 

as you do when you assess their achievement. For more 

information, to ask questions, or to provide comment, 

contact:

Visit the Investi-gator Web site at http://www.scienceinvestigator.org
The Investi-gator • http://www.scienceinvestigator.org 49

Materials and Supplies:

The Investi-gator Vol. 1, #1, Summer 2009

2 X 3 1⁄2 inch sticky notes (11 for each student)

pencils

2 blank unlined pieces of 8 x 11 inch paper for 

each student

National Science Education Standards 

addressed: 

Content Standards A, C, and F

A: Abilities necessary to do scientific inquiry

A: Understandings about scientific inquiry

C: The characteristics of organisms

C: Organisms and their environments

F: Changes in environments

F: Types of resources

Time needed: Two days, 1.2 classroom periods 

(First classroom period: Fifteen minutes)

Classroom Period 1:

Fifteen minutes: Introduce the scientific process, 

as expressed in scientific writing, to your students. 

Explain that scientists communicate with each other 

in writing by completing a scientific paper. A scientific 

paper is similar to what they do when they write a research paper. A scientific paper may have a number 

of sections, but they usually include: 

1. Introduction section. The introduction gives the 

background of the research problem. It explains what 

the problem is and why it is a problem. It usually ends 

with a statement of the question the scientist wanted 

to answer or the specific problem to be solved. 

2. Methods section. The methods section explains 

what kind of data or information the scientist collected, how it was collected, and how it was analyzed. 

3. Findings section. The findings section presents 

the results of the data analysis and usually includes 

an interpretation of the analysis. An interpretation of 

the analysis is different than the analysis itself. The 

analysis is a process of data or information reduction, 

and may include mathematical and statistical processes. Mathematical and statistical analysis are not 

mandatory, as many forms of analysis may include 

non-numerical processes. The interpretation is the 

meaning given to the analysis. Different scientists 

could even interpret the same data or information in 

different ways.

4. Discussion (or Implications) section. In this 

section, the scientist usually discusses the findings 

and interpretation in light of the original problem 

presented in the Introduction section. In addition, this 

section often suggests new questions or problems to 

be answered or solved.

Explain to your students that there are many ways to 

solve scientific problems or answer scientific questions. The type of data or information collected and 

the way it is analyzed depends on the problem or 

question. Introduce the Investi-gator by telling them 

that they will be reading a scientific paper written at 

their grade level. Tell them that this paper is based on 

an actual scientific paper written by scientists working 

for the U.S. Forest Service, a United States government agency.

Hand each student an Investi-gator. For homework, 

ask students to read the article that you have chosen. 

Students should read the entire article, but they do 

not need to read the FACTivity or the Reflection 

Questions.

Lesson Plan for the Investi-gator

Vol. 1, # 1, Summer 2009
50 The Investi-gator • http://www.scienceinvestigator.org 

Classroom Period 2: This will take the entire 

classroom period.

Twenty minutes: Before getting started, give each 

student 11 sticky notes and two pieces of unlined 

white paper. Students will fold one sheet of paper in 

half and then into quarters. Then they will unfold the 

paper. In the first quadrant, have them write “Thinking 

About Science.” In the second, have them write, 

“Thinking About the Environment.” They should put 

their name on both pieces of paper.

Divide your class into eight groups. Assign article 

sections to each group as follows:

Group 1—Introduction (and Reflection Question #1)

Group 2—Introduction (and Reflection Question #2)

Group 3—Method (and Reflection Question #1)

Group 4—Method (and Reflection Question #2)

Group 5—Findings (and Reflection Question #1)

Group 6—Findings (and Reflection Question #2)

Group 7—Discussion (and Reflection Question #1)

Group 8—Discussion (and Reflection Question #2)

(If there are three Reflection Questions, select two 

for this exercise. If there is one reflection section 

question, assign the question to two groups.)

All students should silently read “Thinking About 

Science” and “Thinking About the Environment.” 

When they have finished each section, they should 

write the main idea of each section on one sticky note 

and place it on the paper in the correct quadrant. In 

the third quadrant, students should write the article 

section title to which they have been assigned 

(Introduction, Methods, etc.). Then, each student 

will silently scan that article section, including 

the Reflection Question to which they have been 

assigned. Students should write what they believe to 

be the main idea or main sentence of each paragraph 

on one sticky note, and place each sticky note in one 

of the remaining quadrants. (Have extra blank sheets 

available if needed.) Students should number each 

sticky note in order (#1 for the first paragraph, #2 for 

the second, etc.). Remind students to examine the 

photos, illustrations, and tables in their section.

Ten minutes: Each group will focus specifically on 

the article section and reflection question to which 

they have been assigned. For example, students in 

groups 1 and 2 will focus only on the Introduction. 

Using the sticky note paragraph summaries, groups 

should discuss and develop an answer to their 

reflection question. One student will be appointed 

recorder and one student will be the presenter. The 

reflection answer should be summarized so that its 

presentation will take no longer than one minute 

to answer. The summarization should include a 

rationale for the answer, if necessary. For example, 

“We answered this way because.....”

Twelve minutes: The presenter from each group will 

present the reflection section answer and rationale 

to the class. Have the student read the reflection 

question before giving the answer and rationale.

Note that possible answers to the Reflection 

Section questions are on page 55.

If you have time, hold a class discussion about the 

article. What did students learn? What did they like 

and dislike about the article? Challenge students to 

discuss how the research they just read might affect 

them personally. How might it affect their community?

Assessment: Have students turn in their sheets. You 

should have a “quadrant sheet” from each student, 

and a summary sheet from each group. You can 

assess student comprehension by examining their 

paragraph summary statements.
The Investi-gator • http://www.scienceinvestigator.org 51

 Assessment Rubric

Poor

1

Fair

2

Good/

Satisfactory

3

Exemplary

4

Score

Quadrant sheet

Did not attempt 

to make quadrant 

sheet

Made quadrant sheetnot completedCompleted 

quadrant sheetmissed one section

Complete 

quadrant sheet

Understanding 

of

Material

Did not 

demonstrate

understanding of 

material

Limited

understanding 

demonstrated

Demonstrated

understanding of 

assignment and 

material

Added extra 

evidence to 

support answers

Grammar/

Punctuation More than 8 errors 4–8 errors 1–3 errors No errors

Group 

Summary

Sheet

Group did not turn 

in summary sheet

Showed limited 

support to group 

sheet

Met most of 

criteria for group 

summary sheet

Completed 

group summary 

sheet with full 

participation 

from all members 

of group

Total Score
52 The Investi-gator • http://www.scienceinvestigator.org 

1. The article I read was entitled:________________________________________________ 

Circle the answer that best describes how you feel about the article you just read.

2. The article was: Easy to understand Hard to understand Very hard to 

 understand

3. The article was: Very interesting to read Somewhat interesting Not interesting 

 to read to read

4. Did you learn something from reading the article? Yes No

5. Did you try to answer the Reflection Questions? Yes No Some of 

 them

If you read and tried to answer any of the reflection 

questions, did they help you to think about the article? Yes No

6. Would you like to read another article? Yes No

7. How old are you? 7 8 9 10 11 12 Other age: 

8. What grade are you in? 2nd 3rd 4th 5th 6th Other 

9. Are you a girl or a boy? Girl Boy

Now write in your answer:

10. What did you learn from reading the article?_____________________________________

______________________________________________________________________________

___________________________________________________________________________ 

 

11. What is your favorite subject in school?_____________________________________

______________________________________________________________________________

___________________________________________________________________________ 

 

Along with your class or by yourself, please send this form to:

Dr. Barbara McDonald

Forest Service

320 Green St.

Athens, GA 30602-2044

PLEASE COPY THIS FORM BEFORE COMPLETING

STUDENTS!

Tell Us What You Think About The Investi-gator!

Thank You!
The Investi-gator • http://www.scienceinvestigator.org 53

PLEASE COPY THIS FORM BEFORE COMPLETING

The Investi-gator Teacher’s Evaluation

For each article that you read, please answer the following:

Name of Article: 

1. Would this article help you meet any of the required statewide science curriculum standards? 

Yes No

2. How close to the appropriate reading and comprehension level for your students is this article written?

 Very close Somewhat close Not close

3. If the article is somewhat close or not close to the appropriate reading and comprehension level, is it: 

Too hard Too easy

4. Would or did you use this article in your classroom as an educational resource?

 Yes No Why or why not? 

 

5. Please rate the article sections on a scale of 1 to 5. One means the section was not useful at all, five means 

the section was very useful.

 Not useful Very useful

Meet the Scientist 1 2 3 4 5

Glossary 1 2 3 4 5

Thinking About Science 1 2 3 4 5

Thinking About the Environment 1 2 3 4 5

Introduction 1 2 3 4 5

Methods 1 2 3 4 5

Results 1 2 3 4 5

Graphs, figures, photos 1 2 3 4 5

Reflection Questions 1 2 3 4 5

FACTivity 1 2 3 4 5

PLEASE CONTINUE THIS EVALUATION ON THE NEXT PAGE.
54 The Investi-gator • http://www.scienceinvestigator.org 

For any of the sections you rated with either a one or a two in question 5, please indicate why the section 

was not useful or how it can be improved:

Meet the Scientist 

Thinking About Science 

Thinking About the Environment 

Glossary 

Introduction 

Methods 

Results 

Graphs, figures, photos 

Reflection Questions 

FACTivity 

6. Was the “Note to educators” useful to you?

 Yes No Somewhat

7. What grade(s) do you teach? 

8. What subject(s) do you teach? 

9. Other comments or suggestions:

Thank You!
The Investi-gator • http://www.scienceinvestigator.org 55

Note to Educator: The purpose of the Reflection Section 

Questions is to encourage students to think critically about 

what they have read. The following “answers” are only 

suggestions to assist you in using these questions in the 

classroom. 

Are You Red-dy to Change? Learning 

What Affects Leaf Color Change

Introduction 

What was the research question the scientists wanted to 

answer? Are the air temperature, the length of daylight, 

or the chemicals in the leaves more likely to result in leaf 

color change in sugar maples?

Do you think it is important for people to know when fall 

leaf color will be at its most colorful? Why or why not?

This is an individual question and must be answered 

individually. Students should support their answers with 

logical explanations. 

Method

Why do you think the scientists decided to collect leaf 

samples from June to October instead of from October to 

June? Deciduous trees drop their leaves in the fall and 

winter. If they collected leaves from October to June, 

they would only be able to collect leaves in October and 

November. 

Why is it important for the scientists to take a number of 

leaves from several trees and not just one or two?

Scientists need to collect leaves from more than one or 

two trees so that they get a good sample of leaves from the 

trees. If they only collected leaves from one or two trees, 

there might be something different about those two trees 

than all the other trees. This would throw off their results.

Findings

This study was done in South Burlington, Vermont. Do 

you think late October would be the best time to view 

yellow leaves in Georgia? Why or why not?

This is an individual question and must be answered 

individually. Students should support their answers with 

logical support.

Discussion

Understanding when fall leaf color is at its peak is good 

for a lot of people. What is one of the benefits for store 

owners? One of the benefits for store owners is to plan 

supply orders or they also use it to schedule enough 

employees for the times when many tourists are visiting. 

Give another example of something in nature that attracts 

tourists to an area. If possible, think of an example from 

an area close to where you live. This is an individual 

question and must be answered individually. Students 

should support their answers with logical support. Some 

examples are beaches in the summer and snow for skiing 

in the winter.

No Littering o-Zone: How Rising Ozone 

Levels Affect Tree Growth

Introduction

In your own words and in the form of a question, state 

what the scientists wanted to learn. How do rising ozone 

levels affect tree growth? Here tree growth is determined 

by how many leaves were produced and the amount of 

nutrients in the leaves.

Think about trees growing inside a building and trees 

growing outside. Name three things that make observing 

trees outside more natural than observing them inside.

This is an individual question and must be answered 

individually. Students should support their answers with 

logical support. Examples of some answers are the sun 

is outside, there is rain and other changing weather 

conditions, and insects and animals use the trees as 

habitats.

Possible Answers to the Reflection Sections
56 The Investi-gator • http://www.scienceinvestigator.org 

Method

When people rake leaves in the fall, they take nutrients 

away that could one day become a part of the soil. What 

do people do to their lawns to make up for this?

They add fertilizer to their lawns.

Why do you think the scientists measured the chemical 

content of leaf litter from trees that were not sprayed 

with higher levels of ozone? The scientists measured the 

chemical content of leaf litter from trees that were not 

sprayed with higher levels of ozone so that they could 

estimate how ozone was affecting the forest by comparing 

the measurements between the two sets of trees. 

Do you think scientists must have patience to do some of 

their experiments? What evidence of this can you find in 

the section above. Yes, scientists must be patient. There is 

evidence of this because they have to collect leaves from 

June through October and then come up with their results. 

Also scientists had to wait six years for their results. 

Findings

Based on the findings, do you think that higher levels of 

ozone would be good for trees and other plants growing in 

the forest? Why or why not? Higher levels of ozone are 

not good for trees and other growing plants because there 

are lower levels of leaf litter, carbon, and nitrogen which 

are all important for tree and plant growth. 

If less leaf litter is produced, would growing plants be 

helped or hurt? Explain your answer. Less leaf litter 

hurts growing plants because there are fewer leaves for 

photosynthesis: and each leaf has fewer nutrients, which 

also lowers photosynthesis, and finally fewer nutrients are 

returned to soil as leaf litter falls to the ground.

Discussion

Based on the findings and discussion in this study, do you 

think humans should try to reduce the amount of ozone 

being produced? Why or why not? Humans should try to 

reduce the amount of ozone produced every year so that 

trees and plants will have better growing conditions. 

What is the answer to the scientists’ question? Reread 

the end of the “Introduction” if you have forgotten the 

scientists’ question. The scientists wanted to know how 

rising levels of ozone will affect how trees grow. They 

discovered fewer leaves will grow on trees, and that the 

levels of carbon and nitrogen in the leaves will be lower.

Out of the Penalty Box: Protecting the 

Environment Through Policies

Introduction 

Environmental policies either use penalties or rewards to 

achieve their objectives. Think of two policies that you 

must follow at home or school, one based on penalties 

and the other based on rewards. Think about whether you 

would follow the policy without the penalty or the reward. 

Is one type of policy more effective than the other or are 

they equally effective? Why or why not? You must think 

beyond whether you like the policy. This is an individual 

question and must be individually answered. Students 

should be able to back up their thinking with logic and 

sound reasons.

What are the questions the scientists wanted to answer 

in this study? The first question is: What are the 

characteristics of the policies that have been used to 

manage urban growth and protect urban space? The 

second question is: Which of these types of policies has 

been most effective?

Method

Name at least two of the criteria used by the scientists to 

select which environmental policies to study. 1) Policies 

made by local, State, or Federal governments, 2) Policies 

made after 1980, or 3) Policies made in the United States. 

Think about the last time you chose to buy something. 

This could be a piece of clothing, a CD, or any other item. 

Name two criteria that you used when you decided which 

item to buy. This is a personal question, but the student 

should offer valid criteria. For a CD, for example, criteria 

might include that the music be hip hop, and that it not 

cost over $14. 

Examine figure 4. The third category is land that is or was 

purchased by a government and managed for the public 

good. Name one area in your community that would fit 

into that category. This is an individual question, but 

students should think about their school grounds, public 

parks and recreation areas, local forests, or other public 

lands.

Findings 

Look at the list of four reasons a policy was more 

effective. Which of the four applies most to the policies 

that you must follow at home? Someone keeping a close 

check on whether the policy is being followed.
The Investi-gator • http://www.scienceinvestigator.org 57

In most communities, people can be fined if they throw 

litter on the ground. Into which row and column in figure 

4 would you place this policy? Why would you place it 

there? Control and punishment and protecting open space. 

Because a fine is a penalty and litter on the ground could 

hurt the quality of open space.

Discussion

Think about the conclusions of the scientists, outlined 

in the “Discussion” section, above. Based on these 

conclusions, what is one important aspect of implementing 

a successful policy? Communication among everyone 

involved. Citizens should be involved. 

Do you think it is important to manage urban growth and 

protect open space? Why or why not? This question is 

individual and must be answered by each student. The 

student should be able to back up their answer with reason 

and logic. 

Snowed In? A Closer Look at Soil Activity 

in the Wintertime 

Introduction

What question did the scientists want to answer? The 

scientists wanted to know what happens to the activity of 

microbes if the freezing and thawing cycle happens in the 

natural environment instead of a laboratory setting. 

If soil that never froze before began to freeze during the 

winter, do you think soil activity would be affected? If so, 

how do you think soil activity might be affected? Students 

must answer this individually. However, logic would 

suggest that soil activity would slow down or stop if the 

ground freezes.

Method

Do you think that wintertime soil activity in the 

northeastern United States is similar to wintertime soil 

activity in Canada? Why or why not? Students should 

answer this using logic, and they should back up their 

answers with reason. Logic suggests that wintertime soil 

activity in the northeastern United States would be similar 

to wintertime soil activity in Canada.

Do you think the scientists should have read about research 

done on wintertime soil activity near the equator? Why 

or why not? Students should be aware that the equatorial 

zone is warm year-around, and that research done there 

would not help them understand what happens in cold 

climates during the winter. If this is not clear to some of 

the students, you can use Figure 9 to contrast the climatic 

zones of the equator and the northeastern United States.

Findings

Does the human body produce heat as a result of activity? 

How do you know? Yes. This is evident from perspiration. 

When a person becomes active, they get hotter. 

Restate in your own words what the scientists discovered. 

The scientists found no evidence of greater microbe 

activity when the study was completed in a natural 

environment. This finding was different from what they 

found in a laboratory setting. In the laboratory setting, the 

scientists found that soil microbe activity increased. 

Why do you think the scientists had two different findings 

depending on whether it was a laboratory setting or a 

natural setting? This is an individual question. Students 

should discuss this as a group and make a list of possible 

differences between the two settings and discuss which 

setting may be better for this study. 

Discussion

If you were the scientist, how would you explore whether 

higher average temperatures affect soil activity over the 

entire winter? If one assumes that snow will fall and thaw 

many times over the winter if the average temperature 

is higher than normal, one way to explore this question 

would be to remove snow repeatedly from an area during 

the entire winter. When snow falls, it could be removed by 

shoveling it or heating it with a tool like a hair dryer. Then 

the soil activity could be measured over the course of the 

whole winter. 

Why do you think scientists first tested soil microbe 

activity in a laboratory setting? This is an individual 

question. Students might want to consider the time of year, 

the availability of resources, the availability of money to 

complete the study, etc.
58 The Investi-gator • http://www.scienceinvestigator.org 

Which National Science Education Standards can be addressed 

by this edition of the Investi-gator?

Science Education Standard

No 

Littering

O-Zone

Out of the 

Penalty 

Box

Are You 

Red-dy to 

Change?

Snowed In?

LIFE SCIENCE

The Characteristics of Organisms X X X

Life Cycles of Organisms X

Organisms and Their Environments X X X X

EARTH AND SPACE SCIENCE

Properties of Earth Materials X X

Changes in Earth and Sky X X

SCIENCE AND TECHNOLOGY

Understanding About Science and Technology X X X X

Abilities To Distinguish Between Natural Objects 

and Objects Made By Humans X

SCIENCE IN PERSONAL AND SOCIAL 

PERSPECTIVES

Types of Resources X

Changes In Environments X X X X

HISTORY AND NATURE OF SCIENCE

Science As a Human Endeavor X X X X

SCIENCE AS INQUIRY

Abilities Necessary to do Scientific Inquiry X X X X

Understandings About Scientific Inquiry X X X X

Article 
The Investi-gator • http://www.scienceinvestigator.org 59

The Northern Research Station is a collection of 

scientists and others working at laboratories across 

20 States (figure 1). These States include some of 

the country’s largest cities. These 20 States also 

have some of the country’s most heavily forested 

areas. Across these 20 States, many scientists focus 

their research in four broad areas:

1. Protecting people and forests from

unwanted effects of disturbances. Disturbances 

include events like floods, hurricanes, and the 

spread of unwanted insects and diseases.

2. Improving the quality of life in urban areas 

by taking care of the area’s natural resources. 

Natural resources include water, minerals, oil 

and other things that are provided naturally and 

provide a source of wealth. 

3. Maintaining and enhancing the benefits that 

people receive from forests. These benefits 

include forest products as well as things like clean 

air and water, scenery, and outdoor recreation.

What is the Forest Service?

The Forest Service is a part of the United 

States Department of Agriculture (USDA). It 

is made up of thousands of people who care for 

the Nation’s forest land. The U.S. Forest Service 

manages over 150 national forests and almost 

20 national grasslands. These are large areas of 

trees, streams, and grasslands. National forests 

are similar in some ways to national parks. Both 

are public lands, meaning that they are owned 

by the public and managed for the public’s use 

and benefit. Both national forests and national 

parks provide clean water, homes for the animals 

that live in the wild, and places for people to 

do fun things in the outdoors. National forests 

also provide resources for people to use, such 

as trees for lumber, minerals, and plants used 

for medicines. Some people in the U.S. Forest 

Service are scientists, whose work is presented 

in the journal. Forest Service scientists work to 

solve problems and provide new information 

about natural resources so that we can make sure 

our natural environment is healthy, now and into 

the future. 

For more information, http://www.fs.fed.us.

What is the Northern Research Station?

4. Increasing the production of clean air and 

water for people.

5. Studying and understanding our natural 

resources. 

For more information, http://www.nrs.fs.fed.us.

Figure 1. The Northeastern United States 

is made up of 20 states.
Lyman Hall Elementary School, Hall County, Georgia

Myers Elementary School, Hall County, Georgia

Investi-gator Review Boards

NRS-INF-08-09