3A70.10-Wilberforce pendulum

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Video: Watch this demo | Demo #2

Instructor’s video

Berkeley demo video

Description: This shows how energy transfers between vertical and torsional modes.


  • Wilberforce apparatus

Setup Procedure:

  1. Set up a ladder under a ceiling rail with an assistant to hold it stead
  2. Secure the clamp to the rail and carefully lower the weighted end
  3. Move the ladder out of the way and adjust the weighted end until it is motionless

Demonstration Procedure:

  1. Carefully pull down the weighted end about 1 ft. then release
  2. Note how the frequency of the translational oscillation and torsional oscillation are the same

Note: Highlighting how the torsional motion reverses at the same time the oscillation reaches a crest is a good way to demonstrate the phenomena here.