Make a Compass with a Magnet

Did you know you can make a compass using a magnet, a slice of cork, a bowl of water and a needle? This mini science project is a great way to learn about magnetism and Earth’s magnetic field.

What is magnetism?

Magnetism is an invisible force that affects certain materials.

You don’t need an especially strong magnet to do this. Ours was from a Learning Resources magnet set.

Make a compass with a magnet instructions

You’ll need

A bowl

Water

Magnet

Slice of cork

Steel needle

How can you make a compass with a magnet?

Stroke the needle with one end of the magnet about 20 times. Make sure you lift the magnet after each stroke.

Fill the bowl of water to near the top and place the cork slice on top so it floats.

Place the magnetised needle on top of the cork. The cork and needle will turn until the needle faces North—South. The needle will line up with the Earth’s magnetic field. If you have a compass, you can check this!

Make sure the magnet is far enough away not to interfere.

Why can you make a compass with a magnet and needle?

The needle is made from steel, which contains iron. Iron particles can be magnetised when stroked with a magnet. The effect is temporary but lasts long enough for you to see the needle act like a compass.

Remember, only iron, steel, nickel, and cobalt are magnetic!

Is the Earth like a magnet?

The inside of the Earth contains a lot of iron, so much that it acts like a HUGE magnet. It produces a magnetic field with field lines concentrated at the poles.

The magnetised needle in this activity lines up with the Earth’s magnetic field, making it act like a compass.

What is a magnetic field?

A magnetic field is an area where magnetic materials experience a force.

You can demonstrate a magnetic field around a magnet using iron filings.

a magnet with iron filings around it showing the magnet field

What is a compass?

A compass contains a magnetic needle which can move freely. The north-seeking pole of a compass points towards the north pole of the Earth. Compasses are used for navigating.