Demonstration of electromagnetic induction, using apparatus designed by Michael Faraday, who first published the observation. The apparatus comprises two coils of conducting wire, with the smaller coil fitting into the larger one. The smaller coil is connected to a battery (out of frame at left). When it is moved through the larger coil, its magnetic field induces a current in the larger coil, which is connected to an galvanometer that shows the induced current. This effect is the basis of the electrical generators that provide our electricity.