1. Jose R. Sanchez Jonathan Ryberg Chris Weisman
How does the air pressure of a basketball affect the height of its bounce?
Jose R. Sanchez
Jonathan Ryberg
Chris Weisman

2. Introduction
Purpose: Ball bounce and air pressure is important for basketball because:
1. Not enough: Dribbling is practically impossible.
Too much: The ball will bounce too much.

3. Introduction
How does the air pressure of a basketball affect the height of its bounce?

4. Hypothesis
If we decrease the amount of air pressure inside the basketball, then it will decrease the bounce height because we are increasing the amount of surface area hitting the ground and thus spreading the energy over a larger area.

5. Materials List Basketball Air Pump with needle and gauge
2 meter sticks
Video Camera
iMovie application

6. Experimental Procedure
Tape two meter sticks against a wall
Use a marker to show the lengths at 50cm, 100cm, and 150 cm.
Use the air pump and gauge to determine the basketball is pumped to 8 psi.
Choose a constant (242.6cm) Drop Height

7. Experimental Procedure (cont.)
Drop the ball from the drop height
Use the video camera to record 3 trials of bounce height
Repeat steps for 4, 6, 10 and 12 PSI using the gauge.
Upload the video to iMovie
Use iMovie to slow down the video to determine the bounce height

8. Our Set-up

9. Experimental Parameters
Independent Variable: Air Pressure (PSI)
Dependent Variable: Rebound Height
Constants: Release Point, Floor.

10. Results 4 PSI 6 PSI 8 PSI Control 10 PSI 12 PSI 80.3 120.3 160.67
Avg. Rebound Height (cm)
80.3
120.3
160.67
168.3
169
Rebound Ratio
.33
.495
.66
.69
.70

11. Results

12. Conclusion The data we collected does support our original hypothesis.
Not only does it support our hypothesis, but the data also provides some additional information. According to our data, as the air pressure in the ball increases beyond 8 psi, the amount of rebound ratio is not affected as much.
However, as we decrease the air pressure so that it is less than 8 psi, the bounce height is affected is much more.

13. Conclusion:Science Content
The amount of air molecules increases as the amount of air pressure increases. Therefore, the air molecules will have less room to move when the ball hits the ground.
According to Newtown’s 3rd Law of Motion, as the ball hits the ground there is an equal and opposite force pushing the ball upward.

14. Sources of Error Release Mechanism - Human Error
PSI not exactly at predetermined level

15. Further Questions to Investigate
How does temperature affect the rebound ratio of a basketball?(Internal energy of the air molecules)
How does the surface affect the rebound height?
Which material of the basketball is the best?