Archimedes was the first scientist to use the power of the lever. This
gifted Greek

mathematician and inventor once said, "Give me a place to stand
and rest my lever on, and

I can move the Earth." He also discovered the
compound pulley and Archimedes'screw.

Archimedes was a brilliant
mathematician who helped develop geometry. He discovered

the relation between
the surface area and volume of a sphere and those of its

circumscribing
cylinder.

A legend says that Archimedes discovered the principle of
displacement while

stepping into a full bath. He realized that the water that
ran over equaled in volume the

part of his body that was in the water.
Through more experiments, he presumed the

principle of ability to float,
which is called the Archimedes' principle. According to this

principle a body
dipped in a fluid loses as much in weight as the weight of an equal volume

of
the fluid.

Another legend describes how Archimedes uncovered a fraud
against King Hieron

II of Syracuse using his idea of flotation. The king
suspected that a solid gold crown he

ordered was partly made of silver.
Archimedes first took two equal weights of gold and

silver and compared their
weights when put in water. Next he compared the weights of the

crown and a
pure silver crown of identical dimensions when each was put in water.
The

difference between these two comparisons revealed that the crown was not
solid gold.

Archimedes was born in Syracuse, Sicily. He lived there most
of his life. When the

Romans attacked Syracuse, Archimedes invented
weapons to defend the city. He is said to

have suggested a method of
employing mirrors to set enemy ships on fire. After a two year

attack the
Romans finally entered the city, and Archimedes was killed in the next
battle.