Compass Magnetic

This small magnetic compass has a magnetised needle that lines up with the Earth's magnetic field and points to magnetic north. In the classroom it's used to find north, south, east and west, to orient a map, and to show learners how magnetism works.

It's also the simplest way to show that electricity and magnetism are linked. Put the compass next to a wire carrying a current and the needle swings away from north, because the current creates a magnetic field around the wire that pushes on the needle. Which way it swings depends on the direction of the current and where the compass sits relative to the wire.

You can predict the direction of the field with the right-hand grip rule. Point your right thumb in the direction of the current, and your fingers curl the way the magnetic field lines go around the wire.