A model of the sinan, the first compass. The ladle is made of magnetized iron and balances such that it touches the plate in one point only. This allows it to turn and point towards south.

c. 400 - 300 BC.

The second generation compass. It reduces the friction by using a needle suspended from a very sharp point, basically the same technique still used today. This improves the pointing accuracy.

c. 200 BC - 200 AD.

A modern example of the third generation compass. The needle is immersed in fluid to reduce disturbance and keep its pointing capability when the compass is moved. This allows the use of a compass on ships.

c. 1000 - 1200.