How to Make a Compass

This second grade science project is designed as a follow-on to the make a magnet experiment above. We show how to make a compass out of common everyday items, and continue introducing young students to the concept of magnetism.


Strong Bar magnet
Small block of Styrofoam
Small cork, cut so it will float with the flat side up
Plastic or glass bowl large enough to hold the Styrofoam
About a pint of water


The only preparation needed for this second grade science project is to collect the materials in advance.

Project Day
Using a magnet as a compass

Gather everybody around the table you will use for the demo. Tell them in this second grade science project, we will see if it is possible to make a compass.

(If you have not done a compass experiment yet, now might be a good time to take the compass out and show them how it works. A very basic project is available at What a compass does if needed.)

When ready, put just enough water in the bowl so that the Styrofoam will float without hitting the bottom of the container. Balance the bar magnet on top of the Styrofoam and watch what happens!

The “N” part of the magnet will point North. Get the actual compass out. Keep it well away from the magnet or the compass won’t point in the right direction … and show the students what the compass says is North.

Now carefully pick up the bowl of water and try to move around so that the “N” part of the floating magnet points in a different direction. Be sure to let the students see that no matter what direction you turn, the magnet will point North. And … that is precisely the point. We just made a compass out of an old magnet, a bucket of water and some old left-over piece of styrofoam! (Kinda like what MacGyver would do?).
Magnetizing a paperclip

Now take one of the smaller paperclips and unfold it so you have one end with a hook and the rest as a straight piece of wire. Rub the end of the paperclip (without the hook) against the magnet back and forth at least 30 times. Rubbing only about ½” on the end of the paperclip should do just fine. Make sure you magnetized it by trying to pick up another paperclip. Rub it on the magnet again if it appears to be too weak.

Making a paperclip compass

When the wire is magnetized, continue on with this second grade science project by carefully balancing it on the flat cork, then float the whole works in the bowl of water.

It will be slower this time because the magnet is not as strong, but you should see the straight end of the paperclip heading toward North.

What just happened?

For the teacher – The final result for this second grade science project is that both the magnet and the magnetized paperclip try to align their magnetic fields with the earth’s, but the force of friction on the table top acts like glue to keep them from moving. However, when we float these on water, they are able to move freely. When they do that, they point North. If they always point North, we have a compass!

For the students – A magnet “wants” to point North all the time. When we float it on the water, (hang it by a thread, balance it on a pin point, etc), it is free to move like it wants to. When that happens it points North. When it does that all the time, we have a compass.

Summarize by answering the original question: Shouldn’t we be able to make a compass ourselves?

If you need magnets, these kits can help:


With an attraction to magnets and compasses, build both with this project:

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