24-01-2011, 11:25 AM
SATURDAY COLLEGE
Instructor: Oliver Seely, Jr., Professor of Chemistry
Introduction
Tradition tells us that the king was suspicious about the purity of the gold in his crown and asked Archimedes to find a way to determine if it was the real thing. Solving the problem seemed to be impossible because in those days (3rd century B.C.) nothing was known about chemical analysis. One day Archimedes was thinking about the problem while taking a bath. As he lay floating in the bathtub he thought about his "weightless" body. Suddenly he realized that all bodies "lose" a little weight when placed in water, and the bigger their volume, the more weight they lose. He realized that the density of a metal can be found from its weight and its weight loss in water. The weight of the King's crown and its apparent loss of weight in water would tell him if it were made out of pure gold. Archimedes shouted "Eureka!" (I have found it!) and rushed out into the street naked to announce that he had solved the problem. Today the effect he observed is called Archimedes' Principle.
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