My PBL Project

Materials

1: Basketball

1: Tennis ball

1: Roll of Tape

1: String/Yarn

Procedure

The racquetball is placed on top of the basketball and both are dropped simultaneously . After various tries you will notice the basketball bounces at a smaller height and the tennis ball should bounce twice as high and if not tree time.

The Scientific principle

When a basketball is dropped from the height of your chin, it contains a certain amount of potential energy given by gravity. When it hits the floor or a surface on the ground the energy goes from potential to kinetic. When the energy converts, it gives off some of its energy to the ground causing it to heat up, thus creating heat energy. The energy that is left is used to make the ball bounce back up at least to the waist height. The same is caused for a tennis or racket ball. A tennis ball and a basketball are dropped from about chest height. As they fall, they build up speed. When the basketball hits the floor, it bounces and collides with the tennis ball. Just before the balls hit one another they are both moving at the same speed, but the basketball has a larger mass and therefore more momentum. It turns out that the basketball transfers most of its momentum to the tennis ball. This process can be analyzed through the conservation of momentum equation. The result being that the tennis ball bounces very high, and the basketball barely rises off the ground.

Conservation of Momentum Formula:

m₁V_1i+ m₂V_2i = m₁V_1f + m₂V_2f

Safety Procedure

You will need safety goggles in case the tennis ball bounces back towards you or people around you. It is best to perform this experiment in an empty room, so knock down any surroundings.