Nature of Science
Name _____________________________________Per ___
Thumb Wars
What makes a "Class Champion" thumb wrestler? Does thumb diameter, length, or wrist diameter
have an effect on the overall chances of winning a thumb-wrestling match? In this experiment, you
will use the scientific method to find the answers to these questions.
Suggesting an explanation for what you have seen and observed or in other words, forming a hypothesis, is the first step.
To test a hypothesis, you make a prediction. An experiment is often used to test a hypothesis. A controlled experiment is
based on a comparison of a control group with the experimental group. These two groups are identical except for one
factor called the independent variable. During the course of the controlled experiment, you will observe or measure
another factor in both the control group and the experimental group. This is the dependent variable. After the data from
the experiment is collected and organized, it must be analyzed. This is the process of determining whether data are reliable
and whether or not they support the hypothesis or prediction.
The final step in the scientific method is drawing conclusions. Sometimes a model is produced to show your conclusion.
A model is a visual, verbal, or mathematical explanation supported by data. An inference is a conclusion based on fact
rather than on direct observations. Unlike a hypothesis, an inference is not directly testable. A theory may be formed after
many related hypotheses have been tested and supported with much experimental evidence.
Purpose: The purpose of this activity is to identify and use the six steps of the scientific method.
Step 1: Identify the problem you are going to solve.
Step 2: Formulate a Hypothesis.
Step 3: Do an Experiment.
First take measurements of each members battling thumb diameter and length. Next measure the wrist circumference.
Record all measurements in the table below. All measurements are to be done in centimeters.
Team Member Name
Thumb Diameter (cm)
Thumb Length (cm)
Wrist Circumference (cm)
1.
2.
3.
4.
Next follow the procedure below to conduct your thumb war experiment to see if your hypothesis is correct. Be sure to
record your results in step 4.
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Nature of Science
Name _____________________________________Per ___
Procedure: To play the game, a player hooks the four fingers of their right (or left) hand to the four fingers of the other
player’s right (or left) hand and clasps firmly. To start the game, both players must say, “One, two, three, four, I declare a
thumb war.” Both students then try to trap, pin, or capture their opponents thumb for 5 seconds to win. NO
CHEATING! You may only use your thumb to capture your opponent’s thumb – you may NOT use other fingers or your
other hand to win. Your arms MUST stay touching the desk during the thumb war at all times.
Step 4: Record Your Results.
Team Member # vs. Team Member
#
1 vs 2
1 vs 3
1 vs 4
2 vs 3
2 vs 4
3 vs 4
Result (Who is the Winner?)
Repeat the Experiment (only when
you have finished Step 5!)
Step 5: Make a Conclusion.
1. Who won the most rounds of thumb wars in your group?
2. Does that person have the longest thumb in your group? If so how long?
3. What is the independent and dependent variable for this experiment?
4. Was your hypothesis correct (step 2)? Explain.
Step 6: Repeat the Experiment.
Repeat your experiment again to make sure that the results you got originally are correct. Record your results in the table
above in the column that says “Repeat Experiment.”
Step 7: Make a Final Conclusion.
1. Were the new results the same as the original results? Explain.
2. Do your new results support your original hypothesis? Explain.
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Nature of Science
Step 7: Write a Conclusion Paragraph.
Name _____________________________________Per ___
The most important part to every experiment is being able to explain your conclusions. Create a 3 paragraph conclusion
about this experiment. Paragraph one should be about the experiment. What did you do? What was the procedure?
What is your hypothesis? Paragraph two should contain actual data. What did you observe? Which member won the
most rounds in the original experiment and in the repeat experiment? Include actual data findings in this paragraph.
(Also, don’t use group member names---just numbers). Lastly, paragraph three should contain an explanation of your
hypothesis. Was it correct or incorrect? What would you change if you did this experiment for the third time? Also,
don’t forget the most important part…….error. Where did error occur? What could have been a source of error in this
experiment? (Error is defined as what went wrong.)
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