Faraday's Law Demo: Eddy Pendulum

This is a demonstration of the braking effect of eddy currents created through Faraday's law. A sheet of aluminum is attached to the bottom of a pendulum that swings freely through the poles of a horseshoe magnet. As the sheet passes through the poles, the changing magnetic flux in the aluminum generates an emf and currents, called eddy currents, in the aluminum. These currents induce magnetic fields that oppose the motion of the aluminum through the field, slowing its motion.

This demonstration was created at Utah State University by Professor Boyd F. Edwards, assisted by James Coburn (demonstration specialist), David Evans (videography), and Rebecca Whitney (closed captions), with support from Jan Sojka, Physics Department Head, and Robert Wagner, Executive Vice Provost and Dean of Academic and Instructional Services.