Investigating the Effect of Temperature on the Height a Squash Ball Bounce

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Investigating the Effect of Temperature on the Height a Squash Ball Bounce

Aim: To investigate the effect of temperature on the height a squash

ball bounces.

Prediction: I think that the higher the temperature of the squash

ball, the higher the squash ball will bounce. I think that as the

temperature doubles so will the height of the bounce. I think that

they will be directly proportional.

Scientific Knowledge:

If you drop a ball onto a hard floor. It will rebound, but even the bounciest ball will not bounce back to its starting position.

The ball behaves like a spherical spring. When the ball hits the floor it exerts a force on the floor and the floor exerts a force on the ball. This force compresses the ball. The force that the ground exerts on the ball does work on the ball, since it is in the same direction as the displacement. The gravitational potential energy the ball has before it is dropped is converted into kinetic energy while the ball is falling and then into elastic potential energy as the force from the ground does work on the ball. But because the material the ball is made of is not perfectly elastic, friction converts some of the energy into thermal energy.

The elastic potential energy stored in the ball when it has lost all its kinetic energy is converted back into kinetic and gravitational potential energy. However the thermal energy is not converted back.

The ball on the floor acts like a compressed spring. It pushes on the floor with a force proportional to its displacement from its equilibrium shape. The floor pushes back with a force of equal size in the upward direction. This force is greater in size than the weight of the ball. The resultant force is in the upward direction and the ball accelerates upward. When the ball's shape is the shape it has when it is sitting still on the floor, (just slightly squashed), there is no resultant force. When the ball's shape relaxes further, the resultant force is acting downwards. But it already has velocity in the upward direction, so the ball keeps on going upward until its speed has reached zero.