No two sports balls have the same amount of bounce when dropped from an equal height. A number of factors affect this, including weight and air pressure. One way to analyze the factors affecting bounce is to test sports balls of varying sizes and types. Begin by setting up a drop for all the balls to fall from. Use any flat surface, such as a table, ensuring you have a uniform drop throughout the experiment. Place a yardstick against the table to measure bounces. Next, drop several balls from the table, including basketballs, volleyballs, tennis balls, golf balls and baseballs. Record the height of each bounce and determine how size, weight, air volume or the presence of air pressure affected the balls' ability to bounce.
The weather can have an effect on a ball's ability to bounce. In fact, on cold days balls tend to lose some ability to bounce. Test this with two identical baseballs. Place one of the baseballs in the freezer for at least an hour. Remove the baseball from the freezer and drop it along with the room-temperature baseball for a side-by-side comparison. According to Exploratorium, the room-temperature ball bounces 80 percent higher than the frozen baseball. This occurs because the baseball loses elasticity when frozen.
Basic concepts behind bouncing balls include kinetic energy. Kinetic energy describes the energy an object has while in motion. Drop identical balls (such as two baseballs or two basketballs) from varying heights and record the difference in bounce height. The balls should bounce higher when dropped from greater heights. This occurs because of the additional kinetic energy built up with the additional falling distance. Part of the kinetic energy dissipates when the ball contacts the floor and uses the remaining kinetic energy to bounce back up. Thus, higher heights mean more kinetic energy to bounce back
Outside forces such as gravity and friction aren't the only factors affecting the bounce of a ball. The characteristics of each individual ball also play a role in a ball's bounce. Test this theory by filling two identical balls with different amounts of air. For example, overinflate one volleyball and underinflate another. Next, drop both balls from the same height and record which ball bounces higher. The additional air pressure results in greater elasticity and pressure at the surface. This, in turn, results in a higher bounce. A lack of air pressure creates a softer surface, producing little bounce if any at all.