"Eureka!" "Eureka!" - "I have found it!"

Archimedes of Syracuse(c. 287 BC – c. 212 BC) was a Greek mathematician, physicist, engineer, inventor, and astronomer. Archimedes is generally considered to be the greatest mathematician and inventor of antiquity and one of the greatest of all time.

The most widely known anecdote about Archimedes tells how he invented a method for determining the volume of an object with an irregular shape. A new crown in the shape of a laurel wreath had been made for King Hiero II, and Archimedes was asked to determine whether it was of solid gold, or whether silver had been added by a dishonest goldsmith. Archimedes had to solve the problem without damaging the crown, so he could not melt it down into a regularly shaped body in order to calculate its density.

While taking a bath, he noticed that the level of the water in the tub rose as he got in, and realized that this effect could be used to determine the volume of the crown. For practical purposes water is incompressible, so the submerged crown would displace an amount of water equal to its own volume. By dividing the weight of the crown by the volume of water displaced, the density of the crown could be obtained. The density of the crown would be lower than that of gold if cheaper and less dense metals had been added. Archimedes then took to the streets naked, so excited by his discovery that he had forgotten to dress, crying "Eureka!" (meaning "I have found it!")

While Archimedes did not invent the lever, he wrote the earliest known rigorous explanation of the principle involved. His work on levers caused him to remark: "Give me a place to stand on, and I will move the Earth.” Plutarch describes how Archimedes designed block and tackle pulley systems, allowing sailors to use the principle of leverage to lift objects that would otherwise have been too heavy to move