======Stacked Ball Drop======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Categories:** {{$demo.categories}}
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**Alternative titles:** Bouncing Balls Energy Transfer
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====Summary====                   
{{$demo.summary}}



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



====Links==== 
Stacked ball drop - Institute of Physics: 
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Stacked Ball Drop - Physics Girl: 
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📄 Stacked ball drop - Institute of Physics: [[https://spark.iop.org/stacked-ball-drop]]\\


====Variations====
  * 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).

====Safety Precautions====
  * 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.  




====Questions to Consider====
  * 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.)