5A40.30 2 × 2 Electrostatic Induction

Concepts

Electrostatic induction, attraction of opposite charges

Overview

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.

Details

Equipment

  • [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.

Script

  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

References

  • PIRA 5A40.30

Disclaimer

  • Don't attempt this at home!

Last revised

  • 2020

Technicals

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

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.