If you have ever played with a really powerful magnet, you have probably noticed one problem. You have to be pretty strong to separate the magnets again! Today, we have many uses for powerful magnets, but they wouldn't be any good to us if we were not able to make them release the objects that they attract. In 1820, a Danish physicist, Hans Christian Oersted, discovered that there was a relationship between electricity and magnetism. Thanks to Oersted and a few others, by using electricity, we can now make huge magnets. We can also cause them to release their objects.

Electricity and magnetism are closely related. The movement of electrons causes both, and every electric current has its own magnetic field. This magnetic force in electricity can be used to make powerful electromagnet that can be turned on and off with the flick of a switch. But how do you make an electromagnet?

By simply wrapping wire that has an electrical current running through it around a nail, you can make an electromagnet. When the electric current moves through a wire, it makes a magnetic field. If you coil the wire around and around, it will make the magnetic force stronger, but it will still be pretty weak. Putting a piece of iron or steel inside the coil makes the magnet strong enough to attract objects. The strength of an electromagnet can be increased by increasing the number of loops of wire around the iron core and by increasing the current or voltage.

Electromagnets come in all sizes, from little ones that make doorbells ring, to enormous magnets that pick up entire cars. There are many uses for electromagnets; cassette players, VCRs, stereo speakers, and televisions are a few of the uses for smaller electromagnets. Very large electromagnets are also being used in Germany and Japan to lift and drive trains called maglev trains. Maglev trains have no wheels. Instead they use magnets to run above special rails. The magnets actually lift the train above the rails, and because the train is not actually touching the rails, there is no friction. With no friction, the train runs smoothly and very fast, up to 500 km/h (300 mph).

As you can see, the electromagnet is very useful in our everyday lives and has tremendous potential in the future. Ideas are only limited by our imaginations, so dust off your imagination and turn on the electricity to invent new ways of using the electromagnet in your life.