Wrap the 4-inch nail with a coil of 25 to 50 turns of the wire. Connect one end of the coil to one terminal of the knife switch. Connect the other terminal of the knife switch to the battery.

The iron core increases the coil’s magnetic field strength. A simple electromagnet is made by coiling wire around an iron nail. An iron core makes a temporary electromagnet. It loses its ...

The moving magnetic field from the spinning magnets induces a current in the coil of wire. You have made your own electricity generator!