Archimedes was a Greek physicist, mathematician and inventor who lived in the 3rd century BC in the city of Syracuse, a small Greek colony located in southern Italy. He made important discoveries in the field of geometry. It was in the field of Physics that he made the greatest of his discoveries, the buoyancy principle, however his works are very extensive, presenting contributions not only in the area of physics, but also in mathematics and technology.
Archimedes built ingenious inventions that became very popular in his city. One of the most popular inventions was known as the Archimedes screw. This device was widely used in irrigation, not only in Syracuse, but also in other cities, to raise water from one place to another. Archimedes was the first to build and use a pulley system, through which he could move heavy bodies such as a ship. At the request of the king of Syracuse, he even designed and built war devices to protect the city of Syracuse against possible invasion by Roman troops. Among the devices he built is the use of concave mirrors, which were used to make the sun's rays converge on invading peoples.
Despite all his inventions, the best-known story about Archimedes is that he discovered the principle that allows calculating the thrust that acts on a body when immersed in any fluid. It is said that King Hieron gave a portion of gold to a goldsmith to make a crown. When the latter handed over the crown, the king suspected that the goldsmith had replaced a certain amount of gold with silver. Wanting to know the truth, the king charged Archimedes to find out whether or not his accusation was true. It was during a bath that Archimedes noticed that the water rose as he submerged his body, and in this way he discovered that it was possible to solve the problem of the crown. It was thus, quite by chance, that the principle of buoyancy was discovered. After performing several calculations Archimedes confirmed that the crown was composed of gold and silver, that is, it had been tampered with by the goldsmith.
By Marco Aurélio da Silva
Source: Brazil School - https://brasilescola.uol.com.br/fisica/arquimedes-descoberta-empuxo.htm