5A40.30 2 × 2 Electrostatic Induction


Electrostatic induction, attraction of opposite charges


A 2" × 2" beam is placed on top of a low-friction watch glass. A PVC pipe is charged by rubbing fur on it (the pipe becomes negatively charged). The pipe is then held alongside one end of the 2 × 2 such that the board slowly rotates and moves toward the rod.



  • [1] 2" × 2" beam with watch glass
  • [1] PVC pipe
  • [1] Rabbit's fur
  • [1] Modelling clay (Play-Doh)

Classroom Assembly

  1. Balance the 2 × 2 beam on top of a watch glass. Add modelling clay on either end of the beam to balance it properly.

Important Notes

  • Make sure you hear the build up of charge on the rod. This will be indicated by a crackling noise during charging.
  • As with most electrostatic demonstrations, this works best under 50% humidity.


  1. Rub the fur on the PVC rod.
  2. Hold the near one end of the board. Observe the board moves slowly toward the rod.


Additional Resources


  • PIRA 5A40.30


  • Don't attempt this at home!

Last revised

  • 2020


  • The cross-section of the beam is actually slightly smaller than 2" × 2". Lumber sizing is weird.

Related AV

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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.