A compass works by detecting and responding to the Earth's natural magnetic fields. The Earth has an iron core that is part liquid and part solid crystal, due to gravitational pressure. It is believed that movement in the liquid outer core is what produces the Earth's magnetic field.

How does a compass tell direction?

A compass is a tool for determining directions by means of a magnetic needle pointing north. Determining direction is possible by measuring the angle between the object sighted or the desired direction and the magnetized needle. A compass needle always points to magnetic north, which is different than true north.

Why does a compass point north?

The north pole of a compass magnet points toward the north. ... Earth's south magnetic pole is near Earth's geographic north. Earth's magnetic north pole is near Earth's geographic south. That's why the north pole of a compass points toward north because that's where Earth's south magnetic pole is located and they attract.