If you've ever gone hiking in the woods and gotten lost, then you know how important a compass can be. It can save your life!

As you probably already know, a compass works by showing you where north is. Once you know where that is, then you can figure out where south, east, and west are as well.

But why does the compass needle always turn to the north? How does it know? Is the compass just really smart?

Magnets of course! (like you didn't see that one coming?)
The compass needle itself is a magnet. And what other magnet is it being attracted to?
The Earth!

The Earth itself is a very weak magnet, with its north pole at the North Pole, and its south pole at the South Pole. Pretty easy to remember that way. So the compass needle is attracted to the north pole and will move towards it. Get a compass and see for yourself!


Have you ever wondered why sometimes compasses don't work? Put a magnet next to one and watch it go crazy. That's because the pull of the magnet is stronger than the pull of the Earth's magnetic force, so the needle isn't drawn north anymore, but to the nearby magnet.

The compass as we know it wasn't invented until the 16th century. How did sailors navigate then? If the night was cloudy and they couldn't see the coast, they'd be in real trouble.

Luckily for them, they came up with a very simple solution. And it's something that you can try at home.

What you need...

  1. A bowl of water.
  2. A bar magnet, or any sort of long magnet.
  3. Any lid from a jar.
Take the bowl of water, and float the lid in the water. Then place the magnet on the lid. Watch it turn to the north! Then take the lid and spin it around the opposite direction. The magnet will always turn back north and if your magnet is strong enough, actually move through the water.

This is precisely what the sailors used to do way back when. They would have a bowl of water on the ship, and in it floated a piece of wood. Resting atop the wood would be a piece of magnetic metal, which would always point north. Neat!

Take me back!