Magnets

A magnet is an object that creates a magnetic field, an invisible force that can attract certain metals or push other magnets away. Iron, nickel and cobalt are naturally magnetic, while most everyday metals, such as aluminium or copper, are not attracted in the same way. Every magnet has two poles, called the north pole and the south pole.

Opposite poles attract each other, while like poles repel. The magnetic field extends beyond the magnet itself and becomes weaker as the distance increases. Earth also behaves like a giant magnet, which is why a compass needle lines up in a north-south direction. Magnets are found in many objects used every day.

They help electric motors turn, allow loudspeakers and headphones to produce sound, keep refrigerator doors closed and store information in some electronic devices. Powerful electromagnets work differently from permanent magnets because they create magnetism only when an electric current flows through a coil of wire, often wrapped around an iron core.

Their strength can be adjusted by changing the current. Magnets can also temporarily magnetise certain materials placed nearby, but this effect often disappears once the magnetic field is removed. Understanding magnetism has led to technologies that play an important role in transport, medicine, industry and modern electronics.