5K20.20-Eddy currents in a paddle


Video: Watch this demo

Instructor’s video

Description: When the conductive paddle is moved in the magnetic field, induced current loops (eddy currents) are produced.
This induced current interacts with the magnetic field to produce an opposing force. Work must be done to overcome this opposing force.
Electrons in the paddle swirl around to produce thermal energy.


  • Large permanent magnet
  • Metal Paddle

Setup Procedure:

  1. Remove the protective plug from the magnet. Use caution.
  2. When the professor is done, insert the protective plug into the magnet. Use caution.

Demonstration Procedure:

  1. Move the paddle in between the magnet. Notice that the paddle movement is damped when near the magnet.

Strong magnetic field
This is a very powerful permanent magnet. Use caution.

Note: This demonstration is not visually effective. It requires the students to feel it for themselves.