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Experiment
Bouncing
Tennis Balls
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Problem: How do different
surfaces affect how high a tennis ball will bounce?
Research: Look up information
about motion, bouncing, gravity, friction and potential energy.
Hypothesis: Predict which
surface will help the ball bounce highest.
I think that the ______________
surface will help the ball bounce the highest.
Setting Up the Experiment:
Materials:
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tennis ball
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meter stick or metric measuring tape
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a partner to help you with the experiment
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smooth, hard floor: wood, cement or tile
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rough, hard surface: sidewalk
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carpet
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grass
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pillow
Procedure:
Manipulated Variable: different
surfaces on which the tennis ball is bounced (This is the only thing you
can change.)
Responding Variable: The height
of the bounce in centimeters (these are the results that you will
count)
Steps:
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Have your partner hold the meter stick upright
on the first surface. Make sure that the 1cm end of the stick is down against
the surface and the 100 cm end is up on top. You may tape the meter stick
to a wall or prop it up against something if you do not have a partner.
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Hold the tennis ball as high as the top of
the meter stick (100 cm) and let it drop. Watch carefully to see how high
it bounces back up. Record the height on the chart.
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Do three trials and record the height of the
bounce each time.
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Repeat the steps for each surface. Make sure
that you drop the ball from the same height (100 cm at the top of the meter
stick) each time to keep the tests fair. Make sure that you do three trials
for each surface.
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Figure out the "eyeball average" for each
surface. This means that you look at each of the three trials and pick
the number that is in the middle- not the highest, not the lowest. For
example, if the numbers are: 32 cm, 36 cm and 30 cm, the "eyeball average"
would be 32 cm.
Results:
Make a chart like this to record your
results. Then you can graph the averages on a bar graph.
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Height of the Bounce
in cm
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Trial
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Hard, Smooth Surface
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Hard, Rough Surface
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Carpet
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Grass
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Pillow
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1
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2
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3
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Eyeball Average
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Conclusion:
Look over your results. What did you find
out? On which surface was the average bounce the highest? Can you
determine why this happened? Write your conclusion and answer the problem.
Tell if your hypothesis was correct or incorrect.