Key points
Magnetism is an invisible A force is a push or a pull that acts on an object due to the interaction with another object. that affects materials such as iron, steel, nickel and cobalt.
A A device with a magnetised needle. The needle turns to line up with a magnetic field. can be used to detect both the Earth’s The region around a magnet where a force will be experienced. 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
Here's how to make a magnetic compass that points north using the amazing invisible force of magnetism.
And there are only a few things that we need:A long large needle, a piece of cork carefully sliced into a disc (ask an adult if you need some help),a non-metallic bowl of water, a compass, and a fridge.
Yup, a fridge.And no, the fridge is not there in case you get peckish.
So let's begin. Take your needle to the fridge and open the door.You see that strip down the side of the door?That's actually magnetic.It's what keeps the door shut.
Now take the needle and rub the edge down the magnetic strip several times in one direction.Turn the needle each time so that the whole needle has been in contact with the magnet.
Very carefully place the needle on top of the piece of cork.Get your bowl of water and pop the cork in.It should float on the surface.
Now here's the good bit: if you look closely, you should see the cork start moving.Oh, spooky, eh?
Well, not really.It's spinning because the needle picked up some of the magnetic attraction from the fridge door.And because the needle is magnetic, it lines up with the magnetic field of the Earth and points magnetic north.
If you have a compass handy, you can test it.Does the needle point the same way as the compass?Then the experiment worked.
Give it a try yourself
Image caption, WHAT YOU NEED: A bowl of water, cork, sewing needle and a compass.
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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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