pressure: Buoyancy

A body immersed in a fluid experiences a larger upward pressure on its lower surface than a downward pressure on its upper surface because of the difference in height or depth between the two surfaces; this difference in pressure results in a buoyant force that pushes the body upward (see Archimedes' principle). If the weight of the body is less than the buoyant force, the body will rise; if the weight is greater, the body will sink. The buoyant effect of this pressure may be noted in the rise of balloons or other objects filled with gases, such as hydrogen or helium, that are less dense than air.

Sections in this article:

• Introduction
• Tools for Measuring Pressure
• Hydraulic Force
• Buoyancy
• Influences on and Effects of Pressure
• Pressure of Fluids

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