A compass has a magnetic needle that can rotate freely. When a compass is kept at a place, the magnetic needle aligns in a north-south direction . The red arrow of the compass needle is termed as the north pole and the other end as the south pole.
- A simple compass is a magnetic needle mounted on a pivot, or short pin.
- The needle, which can spin freely, always points north. The pivot is attached to a compass card.
- A special kind of compass called a gyrocompass does point to true north.
- The gyrocompass uses a device called a gyroscope, which always points in the same direction.
- Today, large ships carry both magnetic compasses and gyrocompasses