Archimedes’ principle: Quick Facts

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Illustration showing Archimedes' principle: a 5 kg weight is weighed in air, then submerged in water, where it appears to weigh 2 kg; a separate container shows 2 kg of displaced water, demonstrating buoyant force.

Diagram showing how a ship stays upright, with arrows indicating the downward force of gravity at the center of gravity (G) and the upward force of buoyancy at the center of buoyancy (B), both in level and tilted positions.

Why do objects float or sink in water?

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Topics

Why does ice float on water?buoyancy displacement fluid mechanics aerodynamics Navier-Stokes equation austausch coefficient magnetohydrodynamics hydrostatics

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Key People

Portrait of Archimedes by Giuseppe Nogari shows an elderly man with white hair and beard, holding a compass, gazing downward, set against a dark background.

Archimedes

Greek mathematician and inventor

Italian physicist Guglielmo Marconi at work in the wireless room of his yacht Electra, c. 1920.

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Italian-born physicist Dr. Enrico Fermi draws a diagram at a blackboard with mathematical equations. circa 1950.

Physics and Natural Law