When an electric current flows in a wire it creates a magnetic field around the wire.

By winding the wire into a coil we can strengthen the magnetic field. Electromagnets are made from coils like this.

Making an electromagnet stronger

We can make an electromagnet stronger by doing these things:

• wrapping the coil around an iron core

• adding more turns to the coil

• increasing the current flowing through the coil.

The magnetic field of an electromagnet

The magnetic field around an electromagnet is just the same as the one around a bar magnet. It can, however, be reversed by turning the battery around.

Unlike bar magnets, which are permanent magnets, the magnetism of electromagnets can be turned on and off just by closing or opening the switch.