1N30.60 Double Ball Drop


Momentum and energy transfer through inelastic collisions


The basketball and tennis ball are dropped so that they are touching with the tennis ball on top. When they hit the floor, the tennis ball flies off with greatly increased energy and momentum.



  • [1] Basketball
  • [1] Tennis ball

Important Notes

  • This demo works best with hard surfaces. Dropping the balls on carpet dampens the bounce.


  1. Hold the tennis ball and basketball so that they are touching, with the tennis ball on top.
  2. Drop the balls with the basketball on the bottom. The tennis ball will fly off with greatly increased momentum and energy.


Additional Resources


  • PIRA 1N30.60


  • Don't attempt this at home!

Last revised

  • 2019


  • Original construction: purchased.

Related AV

Related demos

  • Collision Balls (Ninja Balls)


If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.