Let's look at magnets, and at what they can do. 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. 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. In a permanent magnet, tiny magnetic regions called domains line up in the same direction.

Here is a rule to keep. It is about staying safe. 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. That can cause serious damage.

Earth is a really big magnet. Its magnetic field begins in its core. A magnetic field is the area around a magnet where its force can be felt. Invisible lines of force flow between Earth's magnetic poles. These poles are not the same as Earth's geographic North and South Poles. Next, let's look up at space.

The Sun sends out a flow of charged particles called the solar wind. Earth is surrounded by a large magnetic shield. It is called a magnetosphere. The shield protects us from harmful charged particles in space. Now let's see how people find their way on Earth.

A compass has a magnetized needle. It turns to line up with Earth's magnetic field. That is why a compass works. Now for a little history of the compass, a small tool with a long past. A lodestone compass was used in navigation as early as 1086. By the 1100s, a compass was used to navigate. People have used a compass for hundreds of years to find their way.

Words to know

• domains: tiny magnet regions
• needle: compass pointer
• lodestone: natural magnet
• magnetosphere: magnetic shield

The short version

A magnet pulls on other magnets and on some iron and steel things. Every magnet has a north pole and a south pole. Opposite poles attract and the same poles push apart. Earth is a really big magnet, and that is what makes a compass work.

Quick facts

• Every magnet has a north pole and a south pole.
• A magnetic field is the area around a magnet where its force can be felt.
• Earth's magnetic field begins in its core.
• Compasses were used to navigate by the 1100s.
• Earth's magnetosphere protects us from harmful charged particles in space.