Chapter 5. What Is an Electric Motor?
An electric motor is a device that turns electrical energy into mechanical energy. In 1821, Michael Faraday demonstrated what was perhaps the first example of an electromagnetic motor (see Figure 5-1). A wire was dangled into a pool of mercury and placed next to a permanent magnet. When a voltage was applied between the mercury and the top of the wire, current flowed. It created a magnetic field, and the end of the wire started orbiting the magnet.
Do not try to build this motor. Mercury is extremely toxic, and even exposure to the vapor can cause long-lasting ...