Why do some things float in water while the others sink? The answer to this question was found by the Greek scientist Archimedes. The principle he formulated is called the Archimedes principle.
The Archimedes principle states that, when anything is immersed in a fluid even partly, it feels an upward push equal to the weight of the fluid it displaces. For instance, a ship launched into the ocean will sink until it displaces water equal to its own weight.
There is an anecdote related to this discovery. King Hiero II of Syracuse wished to give a gold crown to a temple. The king him-self supplied the gold. However, he had a suspicion that the gold-smith mixed some silver to it. The king asked Archimedes to find the truth without damaging the crown. While taking a bath, Archimedes noticed that the level of the water in the tub rose as he got in. He realised that the submerged crown would displace an amount of water equal to its volume. Thus, the Archimedes principle was formulated.
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