9781422284995

Mei continued, “Did you see me clean up the water each time?” Hayato nodded. “There was a bigger mess the time the canister sank than the time it floated. If we could mea- sure it, we’d find that the volume of water displaced, or pushed out, by the canister each time was equal to the volume of the container.” Hayato said, “That makes sense.” “So,” Mei said, “this is why a ship floats. The buoyant force equals the weight of the fluid that was displaced. So a really big, heavy object, like a ship, will float because it has a larger buoyant force. A ship’s hull is pretty big; the volume of water it displaces is significant enough to keep it afloat.”

A Great Greek

Archimedes lived in ancient Greece from 287 b . c . e . until his death in 212 b . c . e . He is credited with having been a mathematician, physicist, engineer, inventor, and as- tronomer. He calculated the formulas for the area of a circle and the surface area and volume of a sphere. He also calculated an accurate approximation of the value of pi and invented machines such as the screw pump and the compound pulley. His inven- tions were used to help protect his home city of Syracuse from invasion. All did not go as planned, however, when the Romans attacked Syracuse in a two-year battle. Archimedes was killed during the siege by a Roman solider, even though there were strict orders that he not be harmed.

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