In physics, buoyancy ( /ˈbɔɪ.ənsi/) is an upward force exerted by a fluid, that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the column than at the top. This difference in pressure results in a net force that tends to accelerate an object upwards. The magnitude of that force is proportional to the difference in the pressure between the top and the bottom of the column, and (as explained by Archimedes' principle) is also equivalent to the weight of the fluid that would otherwise occupy the column, i.e. the displaced fluid. For this reason, an object whose density is greater than that of the fluid in which it is submerged tends to sink. If the object is either less dense than the liquid or is shaped appropriately (as in a boat), the force can keep the object afloat. This can occur only in a reference frame which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction (that is, a non-inertial reference frame). In a situation of fluid statics, the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body.

Read more about BuoyancyArchimedes' Principle, Forces and Equilibrium, Compressible Fluids and Objects, Buoyancy of Air, Density, Beyond Archimedes' Principle

Other articles related to "buoyancy":

Buoyancy - Beyond Archimedes' Principle - Results
... the equations below give a good approximation to the acceleration and the buoyancy force ... Under the forces of buoyancy and gravity alone, the "dynamic buoyancy force" B acting on the object and its upward acceleration a are given by Buoyancy force ... In the case of neutral buoyancy, m is equal to ρfV ...
Aquatic Locomotion - Efficiency - Buoyancy
... organisms have developed organs to compensate for their weight and control their buoyancy in the water ... and watery tissues that maintain their buoyancy ... in Myctophidae without swim bladders), which provide buoyancy ...
Buoyancy Compensator (aviation)
... The static buoyancy of airships in flight is not constant ... necessary to control the altitude of an airship by controlling its buoyancy buoyancy compensation ...
Atmospheric Convection - Overview
... enough momentum, will continue to rise to the maximum parcel level (MPL) until negative buoyancy decelerates the parcel to a stop ... creates an opposite force to counter that from the buoyancy ... This force from buoyancy can be measured by Convective Available Potential Energy (CAPE), or the joules of energy available per kilogram of potentially buoyant air ...
weight" class="article_title_2">Mass Versus Weight - Buoyancy and Weight
... a balloon is fully filled with helium, it has buoyancy—a force that opposes gravity ... effect that low-gravity environments have on weight, buoyancy does not make a portion of an object’s weight vanish the missing weight is instead ... volumes of air—and ultimately the ground—supports the weight a body loses through mid-air buoyancy ...

Famous quotes containing the word buoyancy:

    The boatmen appeared to lead an easy and contented life, and we thought that we should prefer their employment ourselves to many professions which are much more sought after. They suggested how few circumstances are necessary to the well-being and serenity of man, how indifferent all employments are, and that any may seem noble and poetic to the eyes of men, if pursued with sufficient buoyancy and freedom.
    Henry David Thoreau (1817–1862)

    She keeps
    The Topic over intellectual deeps
    In buoyancy afloat. They see no ghost.
    With sparkling surface-eyes we ply the ball:
    It is in truth a most contagious game:
    Hiding the Skeleton, shall be its name.
    George Meredith (1828–1909)