1N30.10 Collision Balls (Newton's Cradle)


Conservation of momentum, conservation of energy


When the first ball is lifted and released, it collides with the rows of stationary balls and its momentum is transferred to the second ball, then the third, the fourth, until it reaches the last ball on the row. The last ball then swings upward with nearly the same momentum as the first ball in accordance to the principle of conservation of momentum. Newton's cradle also demonstrates conservation of energy since the potential energy of the first ball is converted to kinetic energy and then the energy is transferred to the next ball on the line.



  • [1] Newton's cradle


  1. Pull one ball at the end of the row sideways and release it.
  2. Pull two balls at the end of the row sideways and release them.
  3. Other variations include pulling 3 or 4 balls at a time or pulling one on each side.


Additional Resources


  • PIRA 1N30.10


  • Don't attempt this at home!

Last revised

  • 2017


Related AV

Related demos


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.