Magnets: poles, attraction and repulsion
Physics · Key Stage 2 · The School
Two poles, one rule
Every magnet has a NORTH pole and a SOUTH pole, however small you break it. The rule is short: unlike poles ATTRACT, like poles REPEL. Two north poles pushed together resist, and the harder you push the harder they push back. That is why a magnet can be used to test whether something is itself a magnet — only a magnet is ever repelled.
What magnets actually attract
Magnets attract iron, steel, nickel and cobalt — not all metals. Aluminium drinks cans, copper coins and gold rings are not attracted at all. Testing a set of objects and sorting them shows quickly that "magnetic" is not the same as "metal", which is the single commonest mistake here.
A force without touching
Magnetism is a NON-CONTACT force: it works across a gap, and through paper, wood, water and a hand. That is why a paperclip can be dragged across a table by a magnet held underneath. The force weakens quickly as the gap grows — double the distance and the pull falls off sharply, which you can feel by moving two magnets slowly together.
You have two bar magnets, one with its ends unmarked. Bring the marked north end towards each end of the mystery magnet in turn. One end pulls together: that end must be a SOUTH pole, since unlike poles attract. The other pushes away: that is a NORTH pole. You identified both without any label, using nothing but the rule — and you can feel the push through a sheet of card, because magnetism does not need contact.