Wireless Power. A few years ago MIT created a system for transferring power wirelessly.
They transmitted power over a two-meter distance, from the coil on the left to the coil on the right, where it powers a 60W light bulb. Back in 2006, this was a pretty cool thing. Lesson Plan for Making a Speaker Laboratory. ©1995 The Regents of the University of California by Regan Lum Introduction: A speaker is a device that converts an electronic signal into sound.
The speaker you will build (see figure 1) consists of a Styrofoam or paper cup, a coil of wire, a permanent magnet, and a signal source. The electronic signal goes through the coil and creates a varying electromagnet. Homopolar Motor Video « CollegeSlackers.com.