March 2, 2015
Faraday Train video in: Stephen Irons, “The dipolar express: An electromagnetically driven train”, Physics Today 58, 186-188 (March 2015).
Abstract: Recently an eye-catching YouTube video captivated the attention of many members of the TAP-L (Teaching AP-paratus Listserve, http://demoroom.physics.ncsu.edu/tapl/) community. It shows a AA battery with magnets affixed to each end, racing around the inside of a coil of wire (Fig. 1). The cleverness and simplicity of the demonstration was apparent to all. With no internal moving parts, it is not immediately obvious what makes it energetically zip through the coil, but you really want to know