How a compass uses a magnet to find north
Physics · Key Stage 2 · The School
A magnet balanced to spin freely
A compass needle is a thin bar MAGNET, balanced on a pin so it can spin freely. Left alone, it always settles pointing the same way. That is not luck or a special force in the needle alone — it is reacting to something enormous surrounding it.
The Earth itself is a giant magnet
The Earth behaves like an enormous bar magnet, with a north magnetic pole and a south magnetic pole. The compass needle is simply a small magnet reacting to the Earth's much larger one, the same way one small magnet reacts to another. That is the entire trick — nothing about the compass needle is magic.
Reading a compass properly
Hold a compass flat and still, away from other magnets or big metal objects, which can pull the needle off true. Wait for the needle to stop swinging. The red end points to magnetic north. Turn the compass, not yourself, until the needle lines up with the N on the dial.
A pupil holds a compass flat in the playground. The needle settles, red end pointing towards the school gate. That direction is north. To find south-east, they turn the compass dial until SE lines up where the needle points, then walk in the new direction the dial marks. The needle itself never moved during this — only the dial did, because the needle was already correctly pointing at magnetic north the whole time.