How to Make a Simple Compass at Home

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Making a compass is a simple do-it-yourself project that has lots of teaching applications, plus is fun for kids to see in action.

This experiment involves kids making their own compass while teaching about magnetism, navigation, and the Earth’s poles! It’s simple to put together and exciting to see the sewing needle react to the direction you point it.

Let’s dive in and discover more about magnetism!

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How to make the Simple Compass experiment

Supplies you will need

For this experiment, you’ll need:

• Sewing needle
• Magnet (any kind will work, but a stronger magnet is better)
• Leaf
• Bowl of water
• Optional: Paper, pencil, and ruler (to mark directions)

Before you start

The sewing needle has a sharp point, so please watch your children around it.

Instructions

Here is how to do this experiment with your child:

Step 1: Magnetize the sewing needle

Place the sewing needle against a strong magnet and let it sit for a minute.

The sewing needle is attracted to the magnet. As it stays against the side of the magnet, the end of the needle closest to the south pole of the magnet becomes the north pole of the needle (remember, opposites attract in magnetism) and vice versa.

Step 2: Place leaf into the water and ensure it is floating

If you do not have a leaf handy, anything that helps the needle float on the surface of the water without encumbering its movement would work.

Here are some ideas:

• A cork
• Hollowed-out fruit rind (like an orange)
• Piece of foam paper
• Large bottle cap

Step 3: Place the needle in the water

Be sure your water is deep enough that the needle is floating. We want to ensure that the needle can move unencumbered.

Step 4: Test out your new compass

The magnetized needle should slowly start to rotate, looking for a north-south orientation.

The STEM behind the Simple Compass experiment

This experiment teaches:

• Magnetism
• Navigation
• Resourcefulness

How it works

In this experiment, we are using aligning domains to create a magnetized sewing needle for a compass. A domain is the region in which the magnetic fields of atoms are grouped and aligned.

When you bring a magnet close to the sewing needle, the magnetic field from the magnet interacts with the electrons in the needle’s domains. This interaction tends to align the domains in the needle in the same direction as the domains in the magnet. Each domain acts like a miniature magnet, with its own north and south poles.

As more and more domains in the needle become aligned, the needle itself develops its own magnetic field. This is called induced magnetism. The end of the needle closest to the north pole of the magnet acquires the opposite magnetic pole, and vice versa.

Magnetism

We can do more than just induce magnetism in the sewing needle for this experiment; we can teach about magnetism!

At some point in the experiment, allow your child to play with the magnet, including seeing what is magnetic around the room. Chances are, they’ve played with magnets before, but may not be aware of what is going on.

Depending on their age, you can talk about how magnets attract and repel one another depending on how you align them (great place to talk about the north and south poles of the magnet for this experiment!). Play around with two magnets and try to touch two north poles. Did they attract or repel one another?

We can also teach young kids about transferring magnetism!

Our sewing needle is a temporary magnet, which only becomes magnetized when exposed to a magnetic field (the magnet). Once we remove the sewing needle from the magnet, we only have a temporary magnetic field. That’s why the sewing needle’s power to rotate in a North-South orientation fades after a few minutes.

Navigation

The compasses you can buy in stores work similarly to this simple, at-home compass.

A compass uses a permanently magnetized needle that rests on a pivot that allows it to move freely inside the compass.

On the Earth, we have a magnetic field just like the magnetic bar we used in our experiment. If you imagine the Earth’s axis as the magnetic bar, you can visualize how Earth’s magnetic field is laid out.

The north pole of one magnet is attracted to the south pole of another magnet (that second schematic above). When the needle is positioned properly, it will spin to follow the Earth’s magnetic field, showing the direction.

Resourcefulness

Kids can learn to use everyday materials to create something useful and learn from the process.

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More experiments about magnetism to try out with your child

• What’s Magnetic? The pull of magnets on objects
• Magnetic Slime: A fun twist to slime!