Archimedes' Law – Archimedes and a Golden Crown

Archimedes was a scientist who worked for a king. The king gave him a task – how to distinguish a fake crown from a golden crown. In the fake crown, some of the gold was substituted with silver. Archimedes knew that the fake crown would have more volume because silver is less dense than gold and the same mass of silver would have more volume than the same mass of gold. When we put the fake crown and the lump of gold on scales, a balance beam is even when both bodies have the same weight. Then, if we put the whole thing in water, the fake crown because it is more voluminous, will displace more water and therefore have a bigger buoyant force. With this buoyant force, the crown will appear lighter underwater and the balance beam will no longer be even.