Magnetism Reading

Bar magnets Most materials are not magnetic, but some are. A magnetic material can be [blank_start]magnetized[blank_end] or will be [blank_start]attracted[blank_end] to a magnet. These metals are magnetic: [blank_start]iron[blank_end] [blank_start]cobalt[blank_end] [blank_start]nickel[blank_end] [blank_start]Steel[blank_end] is mostly iron, so [blank_start]steel[blank_end] is magnetic too. A bar magnet is a [blank_start]permanent[blank_end] magnet. This means that its magnetism is present all the time and [blank_start]cannot[blank_end] be turned on or off. A bar magnet has two magnetic poles: -[blank_start]north[blank_end] pole (or north-seeking pole) -[blank_start]south[blank_end] pole (or south-seeking pole)

Magnetic fields A magnet creates a magnetic [blank_start]field[blank_end] around it. You cannot see a magnetic field, but you can observe its effects. A [blank_start]force[blank_end] is exerted on a magnetic material brought into a magnetic field. The force is a [blank_start]non-contact[blank_end] 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 [blank_start]north[blank_end] pole and go into the [blank_start]south[blank_end] pole -the field lines are more concentrated at the [blank_start]poles[blank_end] -The magnetic field is [blank_start]strongest[blank_end] at the poles, where the field lines are most concentrated. -Field lines also show what happens to the magnetic fields of two magnets during [blank_start]attraction[blank_end] or [blank_start]repulsion[blank_end]. -Field lines lead from one magnet to the other when the magnets [blank_start]attract[blank_end] each other -Field lines do not lead from one magnet to the other when the magnets [blank_start]repel[blank_end] each other

The Earth behaves as if it contains a giant [blank_start]magnet[blank_end]. It produces a magnetic field in which the field lines are most concentrated at the [blank_start]poles[blank_end]. This magnetic field can be detected using magnetic materials or magnets. The compass A compass comprises: -a [blank_start]magnetic[blank_end] needle mounted on a pivot (so it can turn freely) -a dial to show the [blank_start]direction[blank_end] 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.