Magnetism Reading

Bar magnets

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



is mostly iron, so is magnetic too.

A bar magnet is a magnet. This means that its magnetism is present all the time and be turned on or off. A bar magnet has two magnetic poles:
- pole (or north-seeking pole)
- pole (or south-seeking pole)

Magnetic fields
A magnet creates a magnetic around it. You cannot see a magnetic field, but you can observe its effects. A is exerted on a magnetic material brought into a magnetic field. The force is a force because the magnet and the material do not have to touch each other.

In the diagram, note that:
-the field lines come out of the pole and go into the pole
-the field lines are more concentrated at the
-The magnetic field is at the poles, where the field lines are most concentrated.

-Field lines also show what happens to the magnetic fields of two magnets during or .
-Field lines lead from one magnet to the other when the magnets each other
-Field lines do not lead from one magnet to the other when the magnets each other

The Earth behaves as if it contains a giant . It produces a magnetic field in which the field lines are most concentrated at the . This magnetic field can be detected using magnetic materials or magnets.

The compass
A compass comprises:
-a needle mounted on a pivot (so it can turn freely)
-a dial to show the

The north pole (north-seeking pole) of the compass needle points towards the Earth’s north pole. If the needle points to the N on the dial, you know that the compass is pointing north. This lets you navigate outdoors using a map.