Magnets and how they are used

A magnet attracts objects made of iron, nickel, cobalt and their alloys (for example steel). Every magnet has two poles: north (N) and south (S). Like poles repel and unlike poles attract. The poles cannot be separated: if a magnet is cut in two you get two smaller magnets, each with two poles again. The force is strongest at the poles and weak in the middle. A magnet creates a magnetic field around itself; the field acts through thin paper, water and glass. The Earth is also a huge magnet: its field turns a compass needle along the north–south line, so a compass helps find directions (the north-seeking end of the needle points to geographic north). Strong eruptions on the Sun disturb Earth’s magnetic field – magnetic storms; they can affect satellites and radio communication and strengthen polar lights. Some migrating birds use Earth’s magnetic field to find their way. Magnets are used in loudspeakers and headphones, electric motors and generators, fridge doors, hard disks, MRI scanners in medicine and electric trains. Safety: strong (neodymium) magnets can pinch fingers; swallowing several small magnets is very dangerous – keep them from small children; do not keep magnets near phones, bank cards or pacemakers.