How did Archimedes discover density?

Answer 1

The story goes that he was easing down into the bath and he noticed that the further down he went, the less he weighed and the more water ran out. Since he had been vexed with the problem of how to test a gold crown that the king suspected was alloyed with (cheaper) silver without destroying it, he recognized that he could use the ratio of the mass of the object (crown) compared to the volume of water it displaced and compare it to a known sample of gold. He was so excited by this that he ran through the streets yelling "εὕρηκα!" ("Eureka!") which means "I've found it!" This is currently not a suggested method for presenting a scientific treatise...especially when you are naked. "Any body wholly or partially immersed in a fluid experiences an upthrust equal to, but opposite in sense to, the weight of the fluid displaced." http://en.wikipedia.org/wiki/Archimedes