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In the physical sciences, Pascal's law or Pascal's principle states that for all points at the same absolute height in a connected body of an incompressible fluid at rest, the fluid pressure is the same, even if additional pressure is applied on the fluid at some place. Physical science is the branch of science including chemistry and physics, usually contrasted with the social sciences and sometimes including and sometimes contrasted with natural or biological science. ...
A fluid is defined as a substance that continually deforms (flows) under an applied shear stress regardless of the magnitude of the applied stress. ...
Fluid pressure is the pressure on an object submerged in a fluid, such as water. ...
The difference of pressure due to a difference in elevation within a fluid column is given by: This article is about pressure in the physical sciences. ...
where, using SI units,
ΔP is the hydrostatic pressure (in pascals), or the difference in pressure at two points within a fluid column, due to the weight of the fluid; Hydrostatic pressure is the pressure exerted by a fluid due to its weight. ...
The pascal (symbol Pa) is the SI unit of pressure. ...
ρ is the fluid density (in kilograms per cubic meter); Kilogram per cubic metre is the SI measure of density and is represented as kg/m³, where kg stands for kilogram and m³ stands for cubic metre. ...
g is sea level acceleration due to Earth's gravity (in meters per second squared); g (also gee, g-force or g-load) is a non-SI unit of acceleration defined as exactly 9. ...
The metre (or meter) per second squared is the SI derived unit of acceleration. ...
Δh is the height of fluid above (in meters), or the difference in elevation between the two points within the fluid column.
The intuitive explanation of this formula is that the change in pressure between two elevations is due to the weight of the fluid between the elevations. For other uses, see Weight (disambiguation). ...
Note that the variation with height does not depend on any additional pressures. Therefore Pascal's law can be interpreted as saying that any change in pressure applied at any given point of the fluid is transmitted undiminished throughout the fluid.
Applications
- Pascal's principle underlies the hydraulic press.
- Used in artesian wells, water towers, and dams.
- 'Pascal's burst barrel demonstration': a long and narrow vertical pipe is connected to the contents of a large, sealed barrel. Adding water to the pipe increases the pressure throughout the system. Adding a small amount of water to the pipe is enough to burst the barrel. Scuba divers must understand this principle. At a depth of 10 meters under water, pressure is twice the atmospheric pressure at sea level, and increases by about 100 kPa for each increase of 10 m depth.
- Atmospheric pressure diminishes with height, a fact first verified on the Puy-de-Dôme and the Saint-Jacques Tower in Paris, on the instigation of Blaise Pascal himself. Following the explanation given above, as height increases the mass of air above each unit of surface area decreases.
Hydraulic force increase. ...
Geological strata giving rise to an Artesian well An artesian aquifer is an aquifer whose water is overpressurized. ...
The mushroom-shaped concrete water tower of Roihuvuori in Helsinki, Finland was built in the 1970s. ...
This article is about structures for water impoundment. ...
Scuba diving is swimming underwater while using self-contained breathing equipment. ...
This article is about the unit of length. ...
The pascal (symbol Pa) is the SI unit of pressure. ...
Diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure at any point in the Earths atmosphere. ...
Puy-de-Dôme, a cumulo-dome (tholoid) volcano, is one of the youngest volcanoes in the Chaîne des Puys region of Massif Central in south-central France. ...
Saint-Jacques Tower is one of the monuments of Paris. ...
This article is about the capital of France. ...
Blaise Pascal (pronounced ), (June 19, 1623 – August 19, 1662) was a French mathematician, physicist, and religious philosopher. ...
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