You have probably seen a compass in person. But have you stopped to think about how it works? The compass is an object of geographical orientation developed 2000 BC. It marks the cardinal points and contains a needle that always indicates the North geographical pole, allowing you to orient yourself and find the direction you want to follow.

But how does it work?

In fact the compass is a very simple instrument. Its operation is based on the combination of the magnetism of its needle with the magnetism of the Earth.

The Earth is a large magnet, which has a magnetic field, which like any other has its magnetic north pole (situated near the geographic South pole) and its magnetic South pole (also very close to the geographical North).

As the compass needle is magnetic (a small magnet), with the North and South poles, it suffers the action of the Earth’s magnetic field, whatever the location of the Earth’s surface you are in.

If the compass needle can rotate freely and knowing that opposite poles attract, the north pole of the compass is attracted by the magnetic south of the Earth. This points to the so-called geographic North Pole. In the same way the opposite occurs, the southern part of the compass is drawn by the magnetic north of the Earth, indicating the South geographical pole of the Earth. Defined the geographic North direction a rose of the winds provides any other desired direction.

How to assemble a compass?

To assemble your own compass you will need:

• A magnet
• A needle
• Scotch tape
• Knife without tipo
• Vessel with water
• A cork or piece of styrofoam

To assemble the compass just cut the cork or a piece of styrofoam and leave it about 1 cm high, forming a kind of disk. Then rub one end of the needle on the side of the magnet about 20 times, always in the same direction and being careful not to make round-trip movements. Then take the tape and use it to attach the needle to the disc.

Finally, just place your compass on the vessel with water. If all is right, when you move the needle, it must return to the same place, that is, pointing to the geographical North.