Eureka! (Archimedes’ Law of Buoyancy)

You may have read about the buoyancy theory which was developed by Achimedes in a number of physics books. Do you know how Archimedes discovered the theory of buoyancy?

Achimedes (211-287 BC) was ancient Greek scientist and mathematician. One day, a king asked him to check whether his crown was made of pure gold, or if there was a mixture of silver inside, but Archimedes was unable to melt crown and check the contents of it. This proved to be a tough task him. Archimedes struggied with the problem for a few days with tack of sleep but he was still unable to find a way to examine it.

One day, when he stepped inti a bath tub filled with water, the water began to spill all over the floor. He then thought, The volume of water that spilled out ia equal to the volume of my body.If I take a pile of pure gold which has the same weight as the crown and put it inside the water, then I will be able to measure its volume.I will be able to check whether the crown is made purely of gold by comparing the volume of pure and the crown. If the crown has a greater volume, it will mean that the crown is mixed with something else. He was so excited that when the stepped out of the bath tub, he was not wearing any clothes. Eureka, Eureka, he shouted, which in Greek means I found it.

Once the tests were completed, the results showed that there was something mixed with the gold the crown. The guilt of the goldsmith was proved beyond a reasonable doubt and Archimedes earned the trust of the King once again.

Later, Archimedes futher explained theis phenomenon and concluded it as the Law of Buoyancy, which he described in his 2-part book series, On Floating Bodies, the net upward buoyancy force is equal to the magnitude of the weight of the fluid displaced by the body.

Food for Thought :

The reason why Archimedes found that the volume of water that spilled out from the bath tub was equal to the volume of the object placed in it was because he had spent a long time figuring out a way to identify the purity of the crown. His keen observation enabled him to relate the situation in which he had observed and the problems he had struggled with and he was eventually successful in developing the Law of Buoyancy

Short Stories on Discoveries, Inventions, Innovation & Creativity

AAET and UTAR, 2015

ms 15-16