1A20.10 Gaussian Collision Board (Bean Machine)


Gaussian distribution


Hundreds of tiny balls roll down through a gap and strike an array of hexagonal posts, bouncing between them and eventually landing in one of a number of slots below. The heights of columns of balls will approximate a Gaussian curve.



  • [1] Gaussian collision board

Important Notes

  • The board must be held straight in order to ensure that the balls approximate a Gaussian curve as closely as possible.


  1. Gather all of the tiny balls in the upper reservoir.
  2. Tilt the board so that all of the balls roll to the bottom.
  3. Show the board to the students using the overhead projector. (Optional)


Additional Resources


  • PIRA 1A20.10


  • Don't attempt this at home!

Last revised

  • 2020


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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.