The story of Archimedes (c. 287–c. 212 BC) and the Golden Crown is among the most famous in the history of scientific discovery. According to legend, the king of Syracuse asked the great mathematician to determine whether his splendid crown, the symbol of his kingship, was really made of pure gold.
Archimedes, who specialized in using math to solve just such practical problems, agonized over the puzzle for days. Finally, as he was taking a bath one afternoon, the solution occurred to him. Shouting “Eureka!”—Greek for “I have found it!”—he sprang out of the tub and ran naked into the streets of Syracuse to spread the news.
Born on the island of Sicily in roughly 287 BC, Archimedes was an engineer, theoretical mathematician, astronomer, and inventor. He was known for decoding the behavior of fluids, explaining how levers work, calculating the value of pi—and inventing terrifying new weapons for the Syracusans.
Indeed, many of Archimedes’ inventions arose from the military needs of Syracuse, a Greek-speaking city-state that was at war with Rome for most of the scientist’s lifetime. To help the city’s naval fleet stay afloat, he invented Archimedes’ screw, a device that quickly pumps water out of ships. He also invented the claw of Archimedes, a metal hook anchored onshore that was used to sink enemy ships. His most fantastic military invention was the heat ray—a system of mirrors that was said to concentrate beams of sunlight onto Roman vessels, setting them on fire. (Some scholars have questioned whether his heat ray could actually have worked.)
The eureka moment in the bathtub involved the measurement of volume. Archimedes knew that to determine the composition of the crown, he needed to know its density, since pure gold has a density different from that of other metals. Density, in turn, depends on weight and volume. Archimedes already knew the crown’s weight, and he realized from watching the water level rise in his tub that he could determine the crown’s volume by measuring the amount of water it displaced. (He proved, to the king’s dismay, that the crown was not pure gold.)
Despite Archimedes’ ingenious weapons, tiny Syracuse was unable to withstand the Roman onslaught. In 212 BC, Archimedes was killed by a soldier when the city finally fell to the Roman legions. Historians sometimes mark the death of Archimedes as the end of an era; he was the last major Greek scientist of antiquity, before Rome achieved dominance over the ancient world.
ADDITIONAL FACTS
- The word eureka was adopted in 1953 as the official motto of the state of California in honor of the prospectors who immigrated to the state in the 1840s hoping to strike gold.
- One of the more ambitious projects undertaken by Archimedes was an estimate of the number of grains of sand that would be needed to fill the entire universe. He concluded that it would take roughly 8 vigintillion grains—an 8 followed by 63 zeros.
- A lost work by Archimedes, Stomachion, was rediscovered in 1906 by a Danish scholar at a monastery in modern-day Turkey. It was sold to an anonymous billionaire for $2 million in 1998.
