BUOYANCY ARCHIMEDES’ PRINCIPLE

less density float Objects with less density will float on fluids with greater density. more densitysink Objects with more density will sink in fluids with less density.

Buoyancyupward forceof a fluid Buoyancy: the upward force of a fluid that pushes an object up Force Force: a push or pull Fluid Liquids & gases Fluid: a substance that flows, that has an indefinite shape (takes the shape of its container). Liquids & gases are fluids. Buoyancy Buoyancy is why objects completely or partly submerged in a liquid seem to weigh less than they do in air.Buoyancy

Buoyancy / Density Relationship denser more buoyant force The denser the fluid is, the more buoyant force it has. airwaterfluids water Think about air and water… Both are fluids, but water has a much greater buoyant force than air, because it is more dense.

OR  The volume of an object in water is equal to the volume of the displaced water. "Any object, wholly or partly immersed in a fluid, is buoyed up by a force equal to the volume of the fluid displaced by the object.” Archimedes’ Principle Ancient Greek mathematician, physicist, engineer, inventor, and astronomer. 250 BC

 less than sink.  If the mass of the water displaced is less than the mass of the object, the object will sink.  float  Otherwise the object will float, with the mass of the water displaced equal to or greater than the mass of the object. Archimedes' Principle explains why steel ships float

Gravity vs. Buoyancy-- which one wins? gravitybuoyancy Think of gravity & buoyancy as 2 opposing forces. Gravitybuoyancy Gravity pulls down, buoyancy pushes up. If weight (gravity) is greater than the displaced water (buoyancy), the object will sink. G B, object sinks If the displaced water (buoyancy) is greater than the weight (gravity), the object will float. G B, object floats