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Bouncing Tennis Balls


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:


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)


  1. 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.
  2. 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.
  3. Do three trials and record the height of the bounce each time.
  4. 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.
  5. 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.

Make a chart like this to record your results. Then you can graph the averages on a bar graph.
Height of the Bounce in cm
Hard, Smooth Surface
Hard, Rough Surface
Eyeball Average

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.