A magnet pulls on other magnets. It also pulls on some iron and steel things, such as pins and paper clips. Every magnet has a north pole and a south pole. Opposite poles pull on each other. The same poles push each other away. Here is a rule to keep. Magnets are not for mouths or small children. Loose magnets can hurt children if they are swallowed. So can high-powered magnet sets. If a child swallows more than one, the magnets can pull together inside the body and cause serious damage.

Now let's look inside a magnet, and at how electricity is linked to it. A magnetic field is the area around a magnet. Its force can be felt there. In a permanent magnet, tiny magnetic regions called domains line up in the same direction. Magnetism is caused by the motion of electric charges. An electric current creates a magnetic field. In 1820 Hans Christian Ørsted's discovery showed that electricity and magnetism are related. A changing magnetic field near a conductor can create an electric current in the conductor. Parallel wires carrying current in the same direction attract each other.

Now let's go inside the planet under our feet. Earth is a really big magnet. Its magnetic field begins in its core. The motion of electrically conducting iron in Earth's outer core makes electric currents. Those currents generate Earth's magnetic field. Invisible lines of force flow between its magnetic poles. These are not the same as its geographic poles.

A compass has a magnetized needle. It turns to line up with Earth's magnetic field. That is what makes a compass work. People have used a compass for hundreds of years. A lodestone compass was in use as early as 1086. As of November 2026, Earth's magnetic north pole is moving. This gradual shift must be regularly accounted for in navigation.

Words to know

• domains: tiny magnet regions
• lodestone: natural magnet
• conductor: carries electricity
• needle: compass pointer