A New Version of an Old Demonstration Experiment Using the Elihu Thomson Jumping Ring Apparatus

Abstract

The goal of this paper is to make more widely known an eye-catching demonstration experiment in which a hanging conducting can is made to spin when placed near the iron core of an Elihu Thomson “jumping ring” apparatus. An explanation is given based on Faraday’s law of induced voltages and the magnetic forces due to the core’s fields interacting with the induced currents.