1Q40.30 Rotating Stool and Bicycle Wheel


Conservation of angular momentum


A person at rest is standing on a low-friction platform or chair and holding a spinning wheel. If the person tilts the wheel, she or he will start rotating according to the law of conservation of angular momentum.



  • [1] Wheel
  • [1] Wheel spinner
  • [1] Low-friction platform, chair, or stool
  • [1] Extension cord

Classroom Assembly

  1. Plug in the wheel spinner.
  2. Place the low-friction platform, chair, or stool in a clear spot.
  3. Level the chair, if applicable.

Important Notes

  • Make sure the person demoing the wheel won't hit anything while rotating and has room to stumble off the platform if it is used.


  1. Get a volunteer onto the low-friction apparatus.
  2. Give her or him to hold the wheel with arms straight out.
  3. Spin up the wheel.
  4. Ask the volunteer to tilt the wheel. The volunteer should be rotating as a result. The most dramatic results occur when the axis of rotation is perpendicular to the ground, and the wheel flips over 180 degrees.


Additional Resources


  • PIRA 1Q40.30


  • Don't attempt this at home!

Last revised

  • 2017


Related AV

Related demos

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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.