How to make a magnetic compass guide for KS3 physics students

Key points

Magnetism is an invisible that affects materials such as iron, steel, nickel and cobalt.
A can be used to detect both the Earth’s and the field around other magnets.
This guide will show you how to make your own magnetic detector, a compass.

Watch this video to learn how to make a magnetic compass

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Give it a try yourself

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WHAT YOU NEED: A bowl of water, cork, sewing needle and a compass.
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Rub the needle 50 times along the magnetic strip on a fridge door. Make sure you do this in one direction only.
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Place the magnetised needle onto the piece of cork.
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Gently place the needle and cork into the bowl of water.
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The needle will turn and then come to a complete stop. It will be facing magnetic north. You can check this by placing the compass next to the bowl.

Why does the needle move?

The needle is being affected by the Earth’s magnetic field. One end points towards magnetic north and the other end points south. You can use a compass to check which direction each end is facing.

The Sun is in the South at about midday, so you can also check your compass is working if one end points in that direction. The other end of the needle will be pointing north, away from the Sun.

Where are compasses used?

When it is dark or foggy, ships need to know they are sailing in the right direction. A ship’s navigator uses a compass to check that they are still on course. Explorers also use a compass to help them find their way and avoid getting lost.

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