Purpose The purpose of this project is to determine how tennis balls are affected by different temperature conditions. After this experiment, one will know why tennis balls bounce differently after being left out in various weather conditions.
Hypothesis If tennis balls are left in various temperatures, then the tennis balls left in the warmest environment will bounce the highest because when the temperature rises, the molecules in the tennis ball expand, and put more pressure on the outside of the ball.
Vocabulary Pressure (p) Density (ρ) Gas Constant (R) Temperature (T) Perfect Gas Law (p=ρRT) Molecules
Background Information • A tennis ball bounces because of the gas inside. The gas moves around and pushes on the inside of a ball. When the ball hits the ground the bottom pushes in, then the ball springs back off the court, due to the gas exerting pressure on the inside. • Gasses have unorganized molecules that take the shape of their container • Gasses are compressible and expandable • When temperature increases, molecules move around more and expand, therefore putting more pressure on the outside of the ball • When temperature decreases, the molecules compress
Materials • 36 new tennis balls • Freezer • Refrigerator • Oven • Room at room temperature • Thermometer • Large centimeter ruler • Stepstool • Video camera • Hard Surface • Hand • Helper (to video-tape)
Set Up\Procedure Balls heated in oven Balls left at room temperature Balls cooled in refrigerator Balls frozen in freezer Electronic thermometer
Set Up\Procedure (cont.) My ruler My dad video-taping the bounce Where I stood
Collecting Data Observe and video-tape each tennis ball bounce. After completed experiment, review tape and record results.
(-5.5o C) (2.1o C) (20o C) (200o C)
Analysis • The heated tennis balls bounced the highest because as the temperature rose, the molecules expanded and exerted more pressure when the ball bounced • The experiment illustrated the perfect gas law, because it showed that when the temperature rose, so did the pressure • The data for each set of tennis balls had a range of 15 centimeters or lower
Conclusion The bounce of the tennis balls, from highest to lowest, was as follows: • heated tennis balls • room temperature tennis balls (control) • cooled tennis balls • frozen tennis balls
Weaknesses\Improvements • Occasionally the bounce was not captured on the video camera, and it had to be redone. This may explain the larger range of data on the first data series (the frozen tennis balls).