3. When we put current through the coil, it turns into a magnet.
4. It works backwards too - when we move a magnet through the middle of the coil, we get some electricity out!
5. Electricity in this context is a unified flow of free electrons. The magnetism pushes the electrons through the wire. So the magnetic field has to be MOVING in relation to the coil in order to MOVE the free electrons around.
6. In alternating current, the polarity changes fifty or sixty times a second.