The Achievements of Archimedes

     Archimedes lived on the island we call Sicily in the third century B.C. He was a mathematician and inventor. In his active years there, he lived during the Second Punic War, the war between Rome to the north and Carthage to the south. After his father King Hiero the first dies in 215 B.C., his son, King Hiero the Second, switches sides and allies Syracuse to Carthage. Rome then assaults Syracuse using its navy by Marcellus. Archimedes' outstanding brain terrified the Roman navy with original ideas like a giant crane. After a few years of harassing, Rome managed to invade and in 212 B.C. Archimedes, intense thinker, was killed by a Roman soldier.

     Archimedes scientific achievements in that time were amazing. One, he understood the idea of buoyancy. Look at figure 2. Buoyancy is the result of the force of gravity pulling a block down and the force of water pushing the block up. The story is that one day the king asked him to inspect a crown of gold. Suspecting that the crown was not ure, he asked Archimedes to discover how much without destroying it. Archimedes did not know the answer and went to a bathhouse to think. He noticed that the water brimmed over when he stepped into it. Then he immediatel shouted Eureka and ran home. He compared pure gold to a mixture of gold and something else and found the pure gold is heavier and pushes less water out The lighter metal pushes more water out because it is less dense, so the volume will be bigger. Because the volume is bigger, the buoyancy force is bigger, the density is lower. When he compared gold and the crown, the crown pushes more water out and so there was less gold in it! By using this principle Archimedes found out the cheat!

     Two, Archimedes understood the principle of the lever. He didn't invent it but understood how to use it effectivel. The principle is the distance between the supporting point and each point multiply with force is same. So we can hold the object more easily if we understand the multiplication between distance and weight on one side and other. Heavier objects can be lifted with less forc but need a longer distance to do so. After knowing this he said to King Hiero, "Give me a place to stand on, and I will move the earth!" Using this idea, he defended Syracuse for Hiero by building cranes and catapults to harass the Romans, using the physics of the lever.