Magnetism is a force that can be felt by metals such as iron, steel, nickel and cobalt. These are called ferrous metals.
Many other metals do not feel the force of magnetism and are non-ferrous. For example aluminium, a metal that is often used to make cans for fizzy drinks, does not feel the force of magnetism.
Every magnet has two poles, north and south. When the north pole of one magnet is close to a north pole of another magnet, they repel each other, we say that like poles repel. However, if a north pole of one magnet is near the south pole of another magnet, they are drawn together, opposite poles attract.
Some ferrous metals can be made permanently magnetic whilst other ferrous metals are not magnets on their own but become magnetic when another magnet is close to them. These metals lose their magnetism as soon as the magnet is taken away. They are called soft magnetic materials.
What does this "field" look like ?
A magnetic field can be represented by a field diagram. A field diagram is just a series of lines that show where the magnetic field exists, and its direction. All magnets have two poles, where the field is at its strongest. There is a "North" or "North seeking" pole, and a "South" or "South seeking" pole.
Magnetic field lines have arrows on them indicating direction, this is always away from the North, and towards the South.
In the picture above (or animation, depending on whether you're reading this document online or from a printout) you can see that the magnetic field lines are indicated north to south. If you put a bar magnet on top of the piece of white paper, and place a small compass as shown, you will be able to mark out the magnetic field lines as they travel from north to south.
