# Science for beginners- Grade 4+

# What is Science?

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![](media/image1.wmf){width="1.4951388888888888in"
height="1.6604166666666667in"}Science is a discipline like music or
mathematics that has a set of rules to guide actions. Science is used to
find truths by repeated measurements using the senses. This use of the
senses makes it pretty much limited to understanding the physical world.
The key is repeated observations. This repetition usually rules out
chance.

If you flip a coin once and it comes up heads, does that mean it will
always be heads?

Try an experiment: You will need 22 pieces of paper to write on,
something to mark with, 11 classmates or friends, and 11 coins with
different sides

**examples of individual and group tally sheets**

On each piece of paper make two headings; one for heads and one for
tails.

Have one person flip a coin 10 times, and record the results on one
piece of paper.

Have ten people each flip a coin 10 times and record the results on
their individual papers. Add all the totals of heads or tails for the
group of ten to get one total for 10 people and one total for one
person. Is there a pattern of heads and tails? Does one occur a lot more
than the other?

Now, have all 11 people flip their coins 60 times each, recording the
number of times the coin is heads or tails. Add the results of the
entire group of 11 and their sixty tosses.

You've just collected data from repeated observations. Now you need to
figure out what the numbers tell you.

Make three fractions. One will be for the ten tosses of one person with
the total number of times the coin came up heads on top (numerator
position) and the total number of times it came up tails on the bottom
(denominator position). A second fraction will be for the total of 100
tosses for the group of ten. The total number of times the toss came up
heads will be on top, and the total number of times it came up tails
will be on the bottom. The third fraction will be for the six hundred
sixty tosses of the group of 11. Again, the total number of times it
came up heads will be on top and the total number of times it came up
tails will be on the bottom.

1 person 10 people 11 people

heads/ 4 / 52 / 329 /

tails 6 48 331

**examples of possible results**

**ratios**

The three fractions are ratios of heads to tails for the three sets of
tosses.

Reduced they come to 2/3 for one 13/12 for ten and about 109.7**/**110.3
for the group of 11. This last can be rounded off to 110/110.

Are the numerators and denominators pretty close to the same number for
the second and third ratios? If you did more tosses, say a thousand, do
you think they would get even closer to being a reduced ratio of 50/50?
Scientists and mathematicians have done this often enough that we know
now that the more tosses you make, the more likely it is that the
numbers on top and bottom come out the same. This means that for every
coin toss, the coin has about the same chance to come up heads, as it
does to come up tails.

The Big Picture

Chance is important in science. Scientists have to know if what they are
observing is random, or caused by something they are testing. Scientists
also have to know if they are measuring things as a whole or just part
of the picture. For years there was debate about thinning of arctic ice.
Scientists in the US and Canada would say there was open ocean where
there ought to be ice, at the same time scientists in Russia would say
the ice was thicker than normal, or at least normal. It wasn\'t until we
had satellites to look at the entire arctic region and 10 years of data
that the total picture came into focus. If weather in Greenland
dominated the air circulation, ice would build up on one side of the
Earth. If weather in the Bahamas was dominant, ice would build up on the
other side of the Earth. Measurements of the total ice showed there was
less ice overall at the end of ten years than at the beginning, but the
fluctuations of ice from one side of the arctic to the other were
normal.

Sometimes scientists measure things directly like the ice.
![](media/image2.wmf)Sometimes it is easier to measure something related
to what you want to measure. At the park we are monitoring water quality
by measuring the number of frog calls we hear each year. Frog eggs have
no hard shell, and frogs develop to adults in water. Water safe for us
to drink could have chemicals in high enough concentrations to harm frog
development or even stop it. Frogs are more sensitive to some chemicals
than we are. Their sensitivity to chemicals makes frogs good indicators
of water quality. If there are lots of frogs, the water can be presumed
to be relatively safe.

If frogs are under physical stress from pollution or other factors, then
chasing them or trying to catch them might kill them. A person could
spend a lot of time looking for frogs to count them visually, but there
is an easier way to monitor changes in their numbers. We measure
remotely, by listening for their breeding calls. Remote sensing
(measuring without touching) is used a lot in science. Listening for
their calls is not going to show their actual numbers. Over time,
however, it will tell us if there is a change in the numbers. It is fast
and easy for the people doing the count, and will give us information
about changes. Change over time is what we are looking for.

We have to identify the assumptions we are making with this count. There
are things we know, and some really good assumptions, and some
assumptions that are safe, and one we know may be false, but making it
helps eliminate confusion.

We are counting frog calls through the spring and summer for 10 years.
If the numbers of calls remain the same or constant over the ten years,
we can assume that the frog population is also constant. If the frog
population remains constant, we can assume that water quality is also
constant or improving.

If we find that there are fewer frogs at the end of the study than there
were at the beginning, then we will have to start a new investigation to
find out why there are fewer frogs. We can not assume it is water. It
might be weather, or a predator, or some disease that has nothing to do
with water quality.

**Water in a watershed**

We know that water quality in one area affects water quality in other
areas. You can do a simple study of water quality at home or in your
neighborhood by looking at what is happening on the land. Stuff on the
land washes downhill to the water. A watershed is the land water drains
from.

**Question to answer: Where is a watershed?**

You will need a topographic map from an outdoor outfitter or the U.S.
Geologic Service branch of the Department of Interior for the first
method. For the second method you will need several jugs of tap water
and a cup.

**Two methods to answer the question.**

A topography map has numbers printed on lines that show how high the
land is above the ocean. The further apart the lines are, the flatter
the land. The closer they are together, the steeper. There is a
topography map and some practice questions at the end of this document.

Determine from a topography map or experimentation where your water
drains into. On a topography map look for the nearest pond, stream, or
lake to your location. These will be blue. If you can find where you are
on the topography map, you can see how high above the ocean level you
are (elevation). If there are no lines with bigger numbers than your
elevation between your location and the water, you are in this water\'s
watershed.

If you want to do an experiment, fill jugs with water. Bring them and a
cup outside. Fill the cup about halfway with water from the jugs, and
pour the water in the cup onto the ground.

![](media/image3.wmf)

**Question: How can we determine what effect we on the land have on the
watershed?**

You will need:

two potted plants, as nearly identical as possible

a small container of chemicals from your kitchen or home that would
normally be flushed down a toilet or washed down a drain (detergent,
bleach, etc.)

tap water in two containers.

**A way to investigate the impact of household chemicals on the
watershed.**

One way to find out what impacts people have on water, is to take two
nearly identical plants and put them in a windowsill where they will get
good light. On one, put just water. On the other, add different
chemicals you find around your home or neighborhood to the water at
about 1 part chemicals to 3 parts water. Mixing with water is needed
because these chemicals are diluted by water in the watershed. Watch the
plants for several weeks and see if they still look the same. Is one
growing better than ![](media/image4.wmf)the other? Which one? Does this
show an impact of chemicals in the water, or is there another
explanation?

**Question: Does air pollution from cars affect the watershed?**

You will need:

a large plastic bag a way to measure pH 3 potted plants

access to a car tap water & distilled water baking soda and vinegar

**A way to measure the impact of air pollution from cars on the
watershed.**

Are there busses, trucks, lawn mowers and grills producing exhaust that
washes out with the rain? Does this impact the watershed? To find out,
take a large plastic bag, and a cup of water. The pH is the level of
acidity or alkalinity of something, usually a liquid. Test the pH of the
water you will use before the experiment. Put a half cup of water in the
bag and hold the open end of the bag behind the exhaust pipe of a car
for only thirty seconds. Don\'t breath in the fumes! Close the top of
the bag, and swish the water in the bag around, then let it collect in
the bottom again. Test the pH again. Was there a difference in the pH?

Most life forms can only live in a small range of pH. To test the
affects of pH on life forms, take three plants as nearly identical as
possible and put them in a windowsill with good light. Using baking soda
(alkaline), vinegar (acid), and distilled water make three solutions,
one that is acid, one that is alkaline and one that is neutral. Be sure
one matches the results from the car experiment. Acid is a pH below 7.
Alkaline is a pH above 7, and 7 is neutral. Water one plant with the
acid solution. Water a second plant with the alkaline solution and the
third with the neutral solution for several weeks. In all other things
keep them the same. Was there a difference in the plants after a few
months? Can you make an assumption about the effect of auto exhaust on
plant life in a watershed from your observations of the three plants?

![](media/image5.wmf)

**Question: Will lawn and farm fertilizer affect the watershed?**

You will need:

3 clear containers holding 3 cups or more fertilizer

3 cups of water that has been in an aquarium or pond or stream

a marker for the containers 3 nearly identical water plants , gravel

**Measuring the effects of fertilizer and sewage on the watershed.**

Farms and many home yards and septic or sewer systems are sources of
nitrogen and phosphate fertilizer. These may be present in such
quantities that the plants on the farm or yard can\'t absorb them all,
and the excess runs off with the rain. To see what affect this has on
plants living in the water take three clear containers and fill them
with water.

**3 identical containers**

Label the containers 0 for no fertilizer, 1 for a tiny bit of
fertilizer, and one 21/2 for the most fertilizer. If you can get water
from an open stream or pond, that will work best. If you can\'t, ask an
aquarium store if you can have three cups of water from an aquarium they
are cleaning. Add a cup of water from an aquarium\'s water change or
pond or stream to each container. Take three nearly identical plants
from an aquarium store and anchor one plant per container, in gravel at
the bottom of the containers. Set them in a window where they will get
light. Add a tiny bit of fertilizer to one, two-and-a-half times as much
to the other, and leave the third container with just the plant and
water. Over the next three weeks add water to the containers as water
evaporates. Also add tiny amounts of fertilizer to the one with a tiny
amount, and 2 1/2 times that amount to the one marked 2 1/2. Just add
water to the one marked 0. In three weeks look at the containers.

We know green plants must get sun to live. Which plant is getting the
most sun through the water? Which the least? What impact could we assume
fertilizer is having on plants in the wild that live in water?

![](media/image6.wmf)

**Design your own study!**

Consider what interests you in your immediate neighborhood. Then
consider the elements of a science study.

1\) Ask **what can be measured that interests you**. Which senses can be
used? **How will it be measured**? **Are there safety precautions to
take?**

*In our frog study, the calls could be easily and safely measured
without harming people or frogs. We used our ears to listen and our ears
and eyes to map frog calls so we count frogs and not frog calls.*

2\) Is what you are measuring going to give **results you can use** to
draw a conclusion?

*Considering our assumptions about frogs, we can conclude that if we do
the study long enough to rule out weather, then the number of frogs
calling represents the same portion of the population of frogs from year
to year. This will let us conclude that the population data we get
reflects a change, if any, in the total population. It gives us no
information on the total population, only changes over time. This is
fine, because change over time will tell us what we need to know about
the water.*

3\) What equipment or tracking methods do you need to make the
measurements or observations? **Can you get what you need** to do the
study and track results?

*We use an audio tape to identify frog species by their calls, and maps
to track where we hear the calls, and tally sheets to track the species
at each station. We then keep a written record of the tallies over
time.*

4\) How **can you be sure what you are measuring is not a random
occurrence?**

*For our frog count we know weather is a factor in their calling. By
doing the study for at least ten years we will be able, through a lot of
observations, to rule out weather as a factor. There is still an element
of chance, but it is an acceptable level. We do the count the same way
each time, important since different methods would give different
results. If we suddenly switched to a visual count, it would give fewer
frogs than the auditory count. If we changed what time of day we did the
count, that might impact how many calls we heard. It has to be the done
the same way each time.*

5\) What assumptions are you making in your study?

*We identified several assumptions, some better than others, and take
those into consideration in stating our results of the frog count.*

6\) **How will you know if your observation and conclusion are
accurate**?

*For our frog study, we have trained different schools including grade
schools, and adults, repeating the study several times a month. A park
ranger also monitors the counts while they are going on.*

7\) What are all the possible explanations for what you\'ve observed?

*For our frog study, we will be able to rule out, through repeated
observations, weather as a reason for a lack of calling. Our research
before the study showed a lack of food would cause frogs not to call,
but this would also lead to a decline in frog numbers.*

**Suggestions for your study:**

the number or diversity of insects in the soil and surface of the ground
by vegetation type (turf, forest, wetland, meadow)

changes in birds species at a feeder through the year

plant diversity over an area and conditions that might cause it.

plants that attract the most variety of insects for feeding on flowers
or leaves or stems

affects of different kinds of land use on percolation of precipitation

![](media/image7.wmf)

Example of coin toss tally sheet

Individual toss Total group tosses

[Heads Jim Tails]{.underline} [Heads Tails]{.underline}

////// //// Tom 5 5

6 4 Lou 4 6

Rochelle 7 3

Jean 6 4

Tanya 4 6

Matt 2 8

Nuy 7 3

Cathy 5 5

Kit 5 5

Pat 6 4

Totals 51 49

Ratios:

Jim: 6/4 100 tosses: 51/49 660 tosses: 333/333

Topographic Map Exercise

use the topography map below for the following exercises:

![](media/image8.png){width="6.8in" height="4.208333333333333in"}

Note how each line has a break with a number in it. These numbers show
how high the area is above the level of the sea. Answer the following
questions, then check your answers on the next page

1.  Which part of the map is the highest?

2.  Find the 10 foot level. Is the land rising steeper to the right or
    the left?

3.  Which side shows a gradual rise from the 10 foot level?

4.  Note the elevation lines are only shown for every 20 feet of
    difference. Does this mean that 10 feet is as low as the land gets?

5.  Where would you expect to find a creek if there was one?

Answers

1\. The lower right side of the map is 100 feet. It is higher than other
sections shown.

2\. The right is showing a steeper rise (lines close together) that then
levels off some between 70 and 100 feet.

3\. The left shows a gradual rise to 30, then 50, then 70 feet. (lines
wider apart)

4\. No it just means 10 feet is the lowest level shown

5\. Somewhere around the 10 foot elevation.