Compass
Ages: 8+
A compass is a tool for finding direction. A compass works because Earth is a huge magnet. A magnet has two main centers of force, called poles, the North and South Poles. The core of the planet, which is mainly molten iron, creates a magnetic field as it spins around. This is what makes the north and south magnetic poles and how compasses are able to work.
The needle in a compass is made of magnetized metal, usually iron, placed on a pivot or pin, so it can freely turn. The compass needle can detect the magnetic field of the Earth and face the Magnetic North when held level in your hand. The person using the device can then work out all the other directions.