Magnetism: basics

In short: Magnetism is the force between magnetic poles. Like poles repel, unlike poles attract. Every magnet has a north and a south pole.

In more detail: Magnetic fields arise from moving electric charges. In permanent magnets the tiny magnetic domains of the material align uniformly.

In detail

• Magnetic materials: Iron, nickel and cobalt are attracted by magnets. Aluminium, copper and plastic are not.
• Field lines: Outside they run from north to south pole and make the field visible.
• Earth’s magnetic field: The Earth is a huge magnet. A compass aligns with it.
• Electromagnet: Current through a coil creates a magnetic field that can be switched on and off.
• Everyday life: Electric motors, loudspeakers, hard drives and fridge magnets use magnetism. Strong magnets can disturb storage media and pacemakers.