Foundation Lesson I

Laying the Foundation in Physics 29

The Scientific Method
Exploring Experimental Design

Come Fly With Us

This assignment is intended to be a quick and easy guide to the methods scientists use to solve problems.
It should also give you information about how to “wing your way” through your own experiments. You
are going to start by making a model helicopter with the attached instructions. You will be given a
problem question, and it is your job to write a suitable hypothesis. Remember, your hypothesis should
be a possible answer to the problem question and it should be based upon what you already know about
a topic.

GLOSSARY OF WORDS USED IN CONDUCTING EXPERIMENTS

• problem: scientific question that can be answered by experimentation
• hypothesis: an educated prediction about how the independent variable will affect the

dependent variable stated in a way that is testable (This should be an “If…then…”
statement.)

• variable: a factor in an experiment that changes or could be changed
• independent variable: the variable that is changed on purpose
• dependent variable: the variable that responds to the independent variable
• control: the standard for comparison in an experiment; the independent variable is not

applied to the control group
• constant: a factor in an experiment that is kept the same in all trials
• repeated trials: the number of times an experiment is repeated

PURPOSE
In this assignment you will practice applying the steps of the scientific method.

MATERIALS
copy of helicopter model scissors
pen or pencil

Foundation Lesson I

30 Laying the Foundation in Physics

PROCEDURE

1. Find the section labeled Hypothesis on your student answer page. Read the problem question and

respond with an appropriate hypothesis. Remember to use an “If…then…” format.

2. Once you have made your hypothesis, you should test it for accuracy. Cut out and fold the helicopter
following the directions on the bottom of the helicopter page.

3. Stand on a chair and hold your helicopter by the top of the “T” at shoulder level.

4. Drop the helicopter and note whether it spins clockwise or counterclockwise. Repeat this test
several times.

5. Refold the blades so that the square on section Y shows when you look down on top of the
helicopter.

6. Stand on a chair and hold your helicopter by the top of the “T” at shoulder level. Drop the helicopter
and note whether it spins clockwise or counterclockwise.

7. Repeat this test several times.

Foundation Lesson I

Name _____________________________________

Period ____________________________________

Laying the Foundation in Physics 31

The Scientific Method
Exploring Experimental Design

Come Fly With Us

PROBLEM

How will changing the direction that the paper helicopter blades are folded affect the “flight” of the
helicopter?

HYPOTHESIS

ANALYSIS

You have just performed an experiment. Experiments involve changing something to see what happens.
In this case, you refolded the helicopter blades. You made this change on purpose to learn about its
effect on the flight of the helicopter. The parts of an experiment that change are called variables.

When designing an experiment, you should choose one variable that you will purposely change. You
will measure the effect of this independent variable on another variable that you think will respond to
the change. The responding variable is called the dependent variable.

If you kept every variable except the folds the same in each test, you were making it a fair test. Why?
Only the variable you changed could be causing the dependent variable to change because everything
else was kept constant.

To have a fair test, you also need a control, or a standard for comparison. A control for the helicopter
experiment would be an “unchanged” helicopter against which you could compare the results. Your
control is the helicopter before the blade directions are changed. After the blades have been flipped, you
then have your experimental helicopter.

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32 Laying the Foundation in Physics

It is important to note that in some experiments, it is impossible to have a control that is completely
unchanged. For example, let’s say you are trying to determine the effect of light from different light
sources on plant growth. The control plant needs some kind of light in order to live through the
experiment. So, you have to choose one light source—possibly normal sunlight—to be the standard of
comparison.

After you refolded the blades of the helicopter, you dropped the helicopter several times and observed
the results. These repeated trials enable you to be more confident of your results. If you conducted your
experiment only once, the results could be due to an error or a chance event, such as a draft. But, when
you repeat your experiment many times and each time achieve similar results, you can be more
confident that your findings are not due to an error or chance.

Complete the following conclusion questions using complete sentences.

CONCLUSION QUESTIONS

1. In the helicopter experiment, what was the independent variable?

2. What was the dependent variable?

3. List three things you should try to keep constant each time you try this experiment.

Read the following paragraph and answer # 4–10:

Bonita wanted to know if adding mass to her paper helicopter would affect
how long it would stay in the air. She predicted that adding some mass would
help to stabilize the helicopter and keep it in the air longer than a helicopter
without extra mass. She experimented with different numbers of paper clips
attached to her helicopter.

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Laying the Foundation in Physics 33

4. What is the problem question in Bonita’s experiment?

5. What is Bonita’s hypothesis?

6. What is her independent variable?

7. What is her dependent variable?

8. What should her constants be?

9. What can she use for a control?

10. Why should Bonita retest her experiment between 5–10 times?

Foundation Lesson I

34 Laying the Foundation in Physics

PAPER HELICOPTER
MODEL

X Y

INSTRUCTIONS:
1. Cut out the rectangular helicopter (above).
2. Now cut along dotted lines.
3. Fold along the solid lines: section C behind section B, section A behind section B, and
section D behind section B.
4. Complete the helicopter by folding blade X with the dot up and blade Y in the opposite
direction with the square down.

cut here

A B C

D

fold forward fold backward

cut here cut here

fold fold

fold

Foundation Lesson I

Name _____________________________________

Period ____________________________________

Laying the Foundation in Physics 35

The Scientific Method
Exploring Experimental Design

Scientific Method Practice 1

DIRECTIONS: Read the following paragraphs and then answer the questions that follow on a separate
sheet of paper. Use complete sentences to answer all questions. Be sure to restate the question in your
answer.

Science differs from other subject areas in the way it seeks to answer questions. This approach to
problem solving is called the scientific method. The scientific method is a systematic approach to
problem solving. Listed below are the basic steps of the scientific method, in one possible order:

• Stating the problem
• Gathering information on the problem
• Forming a hypothesis
• Performing experiments to test the hypothesis
• Recording and analyzing data
• Stating a conclusion
• Repeating the work

Erika baked a cake for her mother’s birthday. When the cake was taken from the
oven, Erika noticed that the cake had not risen. She guessed that the oven had not
heated to the correct temperature. She set up the following experiment to test her
hypothesis.

First, Erika put a thermometer in the oven. She then turned the oven dial to 375ºF.
She noticed that the preheating light came on when she turned the oven on. She
waited until the preheating light went out, indicating that the oven was up to the
specified temperature. Erika then read the thermometer inside the oven. It read
375ºF. Erika concluded that the oven was heating properly.

Foundation Lesson I

36 Laying the Foundation in Physics

CONCLUSION QUESTIONS

1. What was Erika’s problem? [The problem should be stated as a question.]

2. What was Erika’s hypothesis? [This is an answer to your problem question.]

3. What was Erika’s conclusion? [This states whether your hypothesis was supported.]

4. Which step in the scientific method do you think Erika should do next? Explain your reasoning.

5. List two other hypotheses which might explain why the cake did not rise.