(c) Anthony K. Grafton 2003

Your Own Electromagnet

There are probably magnets sticking on the refrigerator in your house, but have you ever tried to make an electrically-powered magnet? All you need is a nail, a flashlight battery, and a foot or two of insulated wire.

1. Always get Mom or Dad’s permission and help: never try this project alone.

2. Strip enough plastic insulation off of each end of the wire to leave about a half-inch of metal exposed.

3. Wrap the wire in a single layer of tight coils around the nail, leaving several inches of wire free at each end. (The more coils you can get around the nail, the better.)

4. Attach one end of the wire to the positive post of a flashlight battery (the big, square, six-volt kind), and one end to the negative post.

5. Now try to pick up some paper clips or other small nails with your electromagnet. While paper clips are stuck to your wire-wrapped nail, disconnect the wires from the battery and notice that the paper clips fall off!

This is an old but simple way to demonstrate that electricity and magnetism are closely related. When electricity is flowing though the coiled wire, the moving current generates a magnetic field. When the battery is disconnected, the current stops flowing and the magnetic field will disappear.

All sorts of things around the house contain coils of wire used to generate magnetic fields in much the same way as the electromagnet you’ve made, including radio or stereo speakers and most televisions. What else can you think of that uses a magnet, and why do you suppose it’s important to have a magnet that can be turned on and off?