There is a fundamental connection between electrity - moving electrons - and magnetism. Moving electrons have magnetic fields, and magnetic fields make electrons travel curved paths. This is how television and computer monitors 'scan' a picture onto the screen.

Magnetic force can be created by electricity flowing through a wire. The force can be increased by coiling the wire, and can be further increased by coiling it around some iron. If a coil of wire is wrapped around a bar of iron, switching on the current turns the bar into a very powerful magnet, called an electromagnet, or solenoid.

This is an extremely useful property that has many applications. Much of modern technology is based on electromagnetism, such as door bells, telephones, loudspeakers, cassette recorders, television monitors, electric clocks, electric motors, etc.

• Making electricity

When a coil of electric wire is moved near a magnet - or a magnet is moved near a coil -the magnetism draws electrons through the wire, creating an electric current.

• Power stations and generators

Power stations make electricity using generators. In generators, turbines (like fan blades) are turned by running water or by steam heated by burning oil or coal, or by nuclear energy. The turning of the turbines turns banks of electric coils round magnets.

• Electric motors

Just as moving magnets create electricity, so an electric current can make a magnet move. In electric motors, an electric current is sent through a coil wrapped round a magnet. The surge of electricity through the coil makes the magnet turn.

An electromagnet can be switched on and off. Without them, doorbells, electric horns, car starter motors and many other machines could not work.

How many devices can you find in and around your house that depend on magnets? Some depend on electricity, and some may use 'permanent magnets'.

Magnetic forces are fundamental forces that arise due to the movement of electrical charge. Maxwell's equations describe the origin and behavior of the fields that govern these forces (see also Biot-Savart's Law). Thus, magnetism is seen whenever electrically charged particles are in motion. This can arise either from movement of electrons in an electric current, resulting in 'electromagnetism', or from the constant subatomic movement of electrons, resulting in what are known as 'permanent magnets'.

Wrap some insulated copper wire around a large nail or similar piece of iron. Strip the insulation off the 2 ends, and attach to a 1.5 v battery (e.g. AA, C, or D)(e.g. with sticky tape). Move the iron towards some paperclips, it should pick them up.

Wrap more turns of wire to make the magnet stronger, or more batteries, or higher voltage batteries (e.g. 9v). But be careful, the wire may get hot! Disconnect from the battery when finished.