Did You Know? When people exclaim Eureka! they are reenacting a legendary event in the life of the Greek mathematician and inventor Archimedes. While wrestling with the problem of how to determine the purity of gold, he made the sudden realization that the buoyancy of an object placed in water is equal in magnitude to the weight of the water the object displaces. According to one popular version of the legend, he made his discovery at a public bathhouse, whereupon he leapt out of his bath, exclaimed “Heureka! Heureka!” (“I have found it!”), and ran home naked through the streets. The absence of a contemporary source for this anecdote has done nothing to diminish its popularity over the centuries.