Electromagnets can be made stronger by adding more coils to the copper wire or adding an iron core through the coils (for example a nail). The current can also be increased to make the magnetism stronger. British electrician William Sturgeon invented the electromagnet in 1825.
An electromagnet is useful because it can be turned on and off easily (using an electric current), whereas a permanent magnet cannot be turned off and will continue to affect its immediate environment.
Different alloys act differently. Iron stops being an electromagnet very quickly, but steel takes time to wear off. To make an electromagnet, copper wire is wound around an iron rod. The two ends of the wire are connected to the + (positive) and - (negative) side of the battery.
Electromagnets are used in everyday items such as burglar alarms, electric relays and fire bells. Electric motors are basically electromagnets. Their ability to change from the state of non-magnetic to magnetic just by passing an electric current through it allows it to be used in many different items. This ability is used in relays.

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