Ciência Viva

The Compass

The compass is an instrument that points to the Earth’s North Pole. On Earth we can use a compass to guide us because the needle points to the approximate position of the North Pole.

The compass face also shows the South Pole, which is in the opposite direction to North, as well as the position of the Sun at sunrise and sunset. The Sun rises in the East and sets in the West.

The compass rose and the cardinal points
The four directions north (N), south (S), East
E) and west (W) are the cardinal points of
the compass rose.

Take your compass and place it on your hand. Wait until the needle stops moving and then turn to the north. If you live in Portugal and it is daytime, the Sun is almost always behind you. Can you say on which side the sun rises and sets?

Place your compass near a magnet, for instance, very close to the rubber on a fridge door. (The rubber on the door contains a magnet!) What happens?

Try changing the position of the magnet. What happens to the needle of the compass?
Why does your compass always point north?

It is because inside the Earth there is a metal - iron, which acts like a giant compass running from north to south!

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