5A40.30: 2 x 4


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Description: This demonstration shows induction by being able to rotate a large 2×4 piece of wood.


  • 2×4 Wooden beam.
  • Small glass dish
  • Rods and Fur

Demonstration Procedure:

  1. Put the glass dish is on a level surface.
  2. Balance the 2×4 on the dish so that it does not touch the surface (glass dish is used as an insulated pivot).
  3. Show that placing a neutral rod near the neutral board does nothing.
  4. Put a charge on the rod with the fur and bring it near the aluminum foil.
  5. The board will slowly start to rotate toward the rod due to induction.

Note: As with most electricity demos, this works best under 50% humidity.