A ping pong ball is dropped alone, with a golf ball, and then stacked above the golf ball to observe differences in rebound height. The demonstration shows how energy conservation and transfer limit the maximum possible bounce height.

1. Roll a clear plastic sheet into a tube about 30 cm long, slightly wider than a golf ball, and secure it with tape.
2. Stand the tube upright on a bench or table and keep it stable with a clamp or an assistant.
3. Drop the ping pong ball from the top of the tube and measure its rebound height.
4. Repeat with the golf ball, measuring its rebound height.
5. Measure the masses of both balls using a balance.
6. Place the ping pong ball directly above the golf ball and release them together from the top of the tube.
7. Measure the rebound height of the ping pong ball.

Stacked ball drop - Institute of Physics:

Stacked Ball Drop - Physics Girl:

📄 Stacked ball drop - Institute of Physics: https://spark.iop.org/stacked-ball-drop

• Try with balls of different mass ratios (e.g., tennis ball and basketball).
• Use a higher release point to test limits of rebound height.
• Compare results on different surfaces (wood, metal, carpet).

• Stand clear of the rebound path of the ping pong ball when dropped with the golf ball.
• Avoid conducting the experiment near fragile objects, as the ping pong ball may rebound unexpectedly high.

• What percentage of its original drop height does the ping pong ball reach when dropped alone? (Answer will depend on surface and bounce efficiency, typically less than 100%.)
• What would the rebound height be if the bounce efficiency were 100%? (It would return to the original drop height.)
• Why does the ping pong ball reach a much greater height when dropped above the golf ball? (The heavier golf ball transfers its momentum and energy to the lighter ping pong ball.)
• How does energy conservation explain the limits on maximum rebound height? (The total gravitational potential energy before the drop cannot be exceeded after the collision.)