The efficiency of a ball can be calculated by dropping and measuring the height of the bounce. The higher the bounce, the more efficient the ball is. Balls which do not bounce high are less efficient as they have lost energy. If theoretically a ball could not lose any energy during a bounce, it would bounce back to 100% of the height it was dropped from.
Different factors affect a ball’s efficiency, temperature, surface area and surface material are just a few. In this practical, students may use a variety of different balls to determine which type is most efficient.
Equipment requited (per set)
Students may measure the height of the first bounce or count the amount of times the ball bounces in total when dropped from a specific height. Either method should ascertain which type of ball is most efficient.
- Variety of balls (tennis, table tennis, squash, cricket etc)
- Metre rule
- Flat surface (students may vary the surface material e.g. Carpet, stone, grass etc)
Higher ability groups may want to investigate how temperature affects the efficiency of a ball. Squash balls can be heated with a hairdryer to see if it has any effect of the height of the bounce. If they wish to use this method, an Infra red thermometer can be used to effectively measure the surface temperature of the ball before it is dropped. Squash balls work well as the surface is fairly flat and they will absorb heat in a more uniform manner than say, tennis balls.