Bar magnets

Most materials are not magnetic, but some are. A magnetic material can be magnetised or will be attracted to a magnet. These metals are magnetic:

  • iron
  • cobalt
  • nickel

Steel is mostly iron, so steel is magnetic too.

A bar magnet is a permanent magnet. This means that its magnetism is there all the time and cannot be turned on or off. A bar magnet has two magnetic poles:

A bar magnet, with the north and south poles marked. The north pole is marked in red and the south pole is marked blue.The north pole is normally shown as N and the south pole as S

Attract and repel

If you bring two bar magnets together, there are two things that can happen, attraction and repulsion:

  • if you bring a north pole and a south pole together, they attract and the magnets stick together
  • if you bring two north poles together, or two south poles together, they repel and the magnets push each other away

We say that opposite poles attract, and like poles repel.

Testing for magnets

How can you test if a piece of metal is actually a magnet? Seeing if it sticks to a magnet is not a good test, because unmagnetised iron, steel, cobalt and nickel objects will also do this. So you can only show that an object is a magnet if it repels a known magnet.