Let's learn how magnets work. You may have played with one. A magnet pulls on other magnets. It also pulls on some iron and steel things. Pins and paper clips are two. Some stones are natural magnets.

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, they can pull together in the body. That can cause serious damage.

Let's look at the poles. Every magnet has a north pole. It has a south pole too. Opposite poles pull on each other. The same poles push each other away. A magnetic field is the area around a magnet. Its force can be felt there.

Earth is a really big magnet. Its magnetic field begins in its core. Invisible lines of force flow between its poles.

A compass has a magnetized needle. The needle turns to line up with Earth's field. That is why a compass works. People have used a compass for hundreds of years to find their way.

Earth's magnetic poles are not the same as its geographic North and South Poles. Earth also has a large magnetic shield. It is called a magnetosphere. The shield protects us from harmful charged particles in space.

Words to know

• poles: magnet ends
• needle: compass pointer
• core: Earth's center
• magnetosphere: magnetic shield