Electromagnet
Electromagnets are temporary and artificial magnets.They are magnets that are only magnetic when there is a coil of wire with electricity running through it. This is called a solenoid. The strength of the magnet is proportional to the current flowing in the circuit. Electromagnets are used for a variety of purposes. In a simple example, an electromagnet can pick up pieces of iron, nickel, and cobalt. The electricity running through the wire is called a current. The current is a flow of electrons, negatively charged particles.
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 very beneficial 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. Iron stops being an electromagnet very quickly, but steel takes time to wear off. To make an electromagnet, copper wire is wound around a steel 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. 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.
