Why does a ball bounce?
Show answer & explanation
Answer: Stored energy from compression
Air inside pushes it back up — Wrong. While air pressure in the ball helps maintain its shape, bouncing happens because the ball's material compresses and releases elastic energy, not just from air pressure.
Stored energy from compression ✓ — Correct! When a ball hits the ground, it compresses and stores elastic energy, like a spring. This stored energy pushes the ball back to its original shape, launching it upward. Some energy is lost as heat and sound, so each bounce is lower. Materials like rubber store more energy and bounce better!
Ground pushes back like a spring — Wrong. While hard ground does exert a reaction force, it doesn't compress like a spring. The bouncing energy comes from the ball compressing and releasing its stored elastic energy, not from the ground.