Science Magazine May 2014 | Page 6

Buoyancy is the tendency for materials to rise or float in fluid. Another name for buoyancy is “the anti gravity force”. The gravity pulls down and buoyancy pushes up so it evens out. Archimedes' principle indicates that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces.

Moving nutrients in our blood stream, pollen floating through air, planes and boats transporting goods all rely on buoyancy to work.

BUOYANCY

If the average density (the

total mass of the substance

and everything on it divided

by the total volume) is less

than the density of the fluid

then it will float.

Blimps use them to fly. Swim

bladders control their

elevation. Buoyancy pushes

things up well gravity pulls

things down.

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