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| Boilerpipe Text | From Wikipedia, the free encyclopedia
Table of Hydraulics and Hydrostatics, from the 1728
Cyclopædia
Hydrostatics
is the branch of
fluid mechanics
that studies
fluids
at
hydrostatic equilibrium
[
1
]
and "the pressure in a fluid or exerted by a fluid on an immersed body".
[
2
]
The word "hydrostatics" is sometimes used to refer specifically to water and other liquids, but more often it includes both gases and liquids, whether
compressible
or
incompressible
. It encompasses the study of the conditions under which fluids are at rest in
stable equilibrium
. It is opposed to
fluid dynamics
, the study of fluids in motion.
Hydrostatics is fundamental to
hydraulics
, the
engineering
of equipment for storing, transporting and using fluids. It is also relevant to
geophysics
and
astrophysics
(for example, in understanding
plate tectonics
and the anomalies of the
Earth's gravitational field
), to
meteorology
, to
medicine
(in the context of
blood pressure
), and many other fields.
Hydrostatics offers physical explanations for many phenomena of everyday life, such as why
atmospheric pressure
changes with
altitude
, why wood and oil float on water, and why the surface of still water is always
level
according to the
curvature of the earth
.
Some principles of hydrostatics have been known in an empirical and intuitive sense since antiquity, by the builders of boats,
cisterns
,
aqueducts
and
fountains
.
Archimedes
is credited with the discovery of
Archimedes' Principle
, which relates the
buoyancy
force on an object that is submerged in a fluid to the weight of fluid displaced by the object. The
Roman
engineer
Vitruvius
warned readers about
lead
pipes bursting under hydrostatic pressure.
[
3
]
The concept of pressure and the way it is transmitted by fluids was formulated by the
French
mathematician
and
philosopher
Blaise Pascal
in 1647.
[
citation needed
]
Hydrostatics in ancient Greece and Rome
[
edit
]
The "fair cup" or
Pythagorean cup
, which dates from about the 6th century BC, is a hydraulic technology whose invention is credited to the Greek mathematician and geometer Pythagoras. It was used as a learning tool.
[
citation needed
]
The cup consists of a line carved into the interior of the cup, and a small vertical pipe in the center of the cup that leads to the bottom. The height of this pipe is the same as the line carved into the interior of the cup. The cup may be filled to the line without any fluid passing into the pipe in the center of the cup. However, when the amount of fluid exceeds this fill line, fluid will overflow into the pipe in the center of the cup. Due to the drag that molecules exert on one another, the cup will be emptied.
Heron's fountain
is a device invented by
Heron of Alexandria
that consists of a jet of fluid being fed by a reservoir of fluid. The fountain is constructed in such a way that the height of the jet exceeds the height of the fluid in the reservoir, apparently in violation of principles of hydrostatic pressure. The device consisted of an opening and two containers arranged one above the other. The intermediate pot, which was sealed, was filled with fluid, and several
cannula
(a small tube for transferring fluid between vessels) connecting the various vessels. Trapped air inside the vessels induces a jet of water out of a nozzle, emptying all water from the intermediate reservoir.
[
citation needed
]
Pascal's contribution in hydrostatics
[
edit
]
Pascal made contributions to developments in both hydrostatics and hydrodynamics.
Pascal's law
is a fundamental principle of fluid mechanics that states that any pressure applied to the surface of a fluid is transmitted uniformly throughout the fluid in all directions, in such a way that initial variations in pressure are not changed.
Liquids (fluids with free surfaces)
[
edit
]
Liquids can have
free surfaces
at which they interface with gases, or with a
vacuum
. In general, the lack of the ability to sustain a
shear stress
entails that free surfaces rapidly adjust towards an equilibrium. However, on small length scales, there is an important balancing force from
surface tension
.
When liquids are constrained in vessels whose dimensions are small, compared to the relevant length scales,
surface tension
effects become important leading to the formation of a
meniscus
through
capillary action
. This capillary action has profound consequences for biological systems as it is part of one of the two driving mechanisms of the flow of water in
plant
xylem
, the
transpirational pull
.
Without surface tension,
drops
would not be able to form. The dimensions and stability of drops are determined by surface tension. The drop's surface tension is directly proportional to the cohesion property of the fluid.
Communicating vessels
– Set of internally connected containers containing a homogeneous fluid
D-DIA
– Apparatus used for high pressure and high temperature deformation experiments
Hydrostatic pressure
– Physical quantity
Hydrostatic test
– Non-destructive test of pressure vessels
Triaxial shear test
– Stress test with different levels of stress in each perpendicular direction
^
"Fluid Mechanics/Fluid Statics/Fundamentals of Fluid Statics - Wikibooks, open books for an open world"
.
en.wikibooks.org
. Retrieved
2021-04-01
.
^
"Hydrostatics"
.
Merriam-Webster
. Retrieved
11 September
2018
.
^
Marcus Vitruvius Pollio (ca. 15 BCE),
"The Ten Books of Architecture"
, Book VIII, Chapter 6. At the University of Chicago's Penelope site. Accessed on 2013-02-25.
Batchelor, George K. (1967).
An Introduction to Fluid Dynamics
. Cambridge University Press.
ISBN
0-521-66396-2
.
Falkovich, Gregory (2011).
Fluid Mechanics (A short course for physicists)
. Cambridge University Press.
ISBN
978-1-107-00575-4
.
Kundu, Pijush K.; Cohen, Ira M. (2008).
Fluid Mechanics
(4th rev. ed.). Academic Press.
ISBN
978-0-12-373735-9
.
Currie, I. G. (1974).
Fundamental Mechanics of Fluids
. McGraw-Hill.
ISBN
0-07-015000-1
.
Massey, B.; Ward-Smith, J. (2005).
Mechanics of Fluids
(8th ed.). Taylor & Francis.
ISBN
978-0-415-36206-1
.
White, Frank M. (2003).
Fluid Mechanics
. McGraw–Hill.
ISBN
0-07-240217-2
.
The Flow of Dry Water - The Feynman Lectures on Physics |
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## Contents
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- [(Top)](https://en.wikipedia.org/wiki/Hydrostatics)
- [1 History](https://en.wikipedia.org/wiki/Hydrostatics#History)
- [2 Hydrostatics in ancient Greece and Rome](https://en.wikipedia.org/wiki/Hydrostatics#Hydrostatics_in_ancient_Greece_and_Rome)
Toggle Hydrostatics in ancient Greece and Rome subsection
- [2\.1 Pythagorean Cup](https://en.wikipedia.org/wiki/Hydrostatics#Pythagorean_Cup)
- [2\.2 Heron's fountain](https://en.wikipedia.org/wiki/Hydrostatics#Heron's_fountain)
- [3 Pascal's contribution in hydrostatics](https://en.wikipedia.org/wiki/Hydrostatics#Pascal's_contribution_in_hydrostatics)
- [4 Liquids (fluids with free surfaces)](https://en.wikipedia.org/wiki/Hydrostatics#Liquids_\(fluids_with_free_surfaces\))
Toggle Liquids (fluids with free surfaces) subsection
- [4\.1 Capillary action](https://en.wikipedia.org/wiki/Hydrostatics#Capillary_action)
- [4\.2 Hanging drops](https://en.wikipedia.org/wiki/Hydrostatics#Hanging_drops)
- [5 See also](https://en.wikipedia.org/wiki/Hydrostatics#See_also)
- [6 References](https://en.wikipedia.org/wiki/Hydrostatics#References)
- [7 Further reading](https://en.wikipedia.org/wiki/Hydrostatics#Further_reading)
- [8 External links](https://en.wikipedia.org/wiki/Hydrostatics#External_links)
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From Wikipedia, the free encyclopedia
Branch of fluid mechanics that studies fluids at rest
This article is about the discipline branch. For the concept, see [Hydrostatic equilibrium](https://en.wikipedia.org/wiki/Hydrostatic_equilibrium "Hydrostatic equilibrium").
[](https://en.wikipedia.org/wiki/File:Table_of_Hydraulics_and_Hydrostatics,_Cyclopaedia,_Volume_1.jpg)
Table of Hydraulics and Hydrostatics, from the 1728 *[Cyclopædia](https://en.wikipedia.org/wiki/Cyclop%C3%A6dia,_or_an_Universal_Dictionary_of_Arts_and_Sciences "Cyclopædia, or an Universal Dictionary of Arts and Sciences")*
| |
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| Part of a series on |
| [Continuum mechanics](https://en.wikipedia.org/wiki/Continuum_mechanics "Continuum mechanics") |
| J \= − D d φ d x {\\displaystyle J=-D{\\frac {d\\varphi }{dx}}} [Fick's laws of diffusion](https://en.wikipedia.org/wiki/Fick%27s_laws_of_diffusion "Fick's laws of diffusion") |
| [Solid mechanics](https://en.wikipedia.org/wiki/Solid_mechanics "Solid mechanics") [Deformation](https://en.wikipedia.org/wiki/Deformation_\(physics\) "Deformation (physics)") [Elasticity](https://en.wikipedia.org/wiki/Elasticity_\(physics\) "Elasticity (physics)") [linear](https://en.wikipedia.org/wiki/Linear_elasticity "Linear elasticity") [Plasticity](https://en.wikipedia.org/wiki/Plasticity_\(physics\) "Plasticity (physics)") [Hooke's law](https://en.wikipedia.org/wiki/Hooke%27s_law "Hooke's law") [Stress](https://en.wikipedia.org/wiki/Stress_\(mechanics\) "Stress (mechanics)") [Strain](https://en.wikipedia.org/wiki/Strain_\(mechanics\) "Strain (mechanics)") [Finite strain](https://en.wikipedia.org/wiki/Finite_strain_theory "Finite strain theory") [Infinitesimal strain](https://en.wikipedia.org/wiki/Infinitesimal_strain_theory "Infinitesimal strain theory") [Compatibility](https://en.wikipedia.org/wiki/Compatibility_\(mechanics\) "Compatibility (mechanics)") [Bending](https://en.wikipedia.org/wiki/Bending "Bending") [Contact mechanics](https://en.wikipedia.org/wiki/Contact_mechanics "Contact mechanics") [frictional](https://en.wikipedia.org/wiki/Frictional_contact_mechanics "Frictional contact mechanics") [Material failure theory](https://en.wikipedia.org/wiki/Material_failure_theory "Material failure theory") [Fracture mechanics](https://en.wikipedia.org/wiki/Fracture_mechanics "Fracture mechanics") |
| [Fluids](https://en.wikipedia.org/wiki/Fluid "Fluid") |
| [Statics]() **·** [Dynamics](https://en.wikipedia.org/wiki/Fluid_dynamics "Fluid dynamics") [Archimedes' principle](https://en.wikipedia.org/wiki/Archimedes%27_principle "Archimedes' principle") **·** [Bernoulli's principle](https://en.wikipedia.org/wiki/Bernoulli%27s_principle "Bernoulli's principle") [Navier–Stokes equations](https://en.wikipedia.org/wiki/Navier%E2%80%93Stokes_equations "Navier–Stokes equations") [Poiseuille equation](https://en.wikipedia.org/wiki/Hagen%E2%80%93Poiseuille_equation "Hagen–Poiseuille equation") **·** [Pascal's law](https://en.wikipedia.org/wiki/Pascal%27s_law "Pascal's law") [Viscosity](https://en.wikipedia.org/wiki/Viscosity "Viscosity") ([Newtonian](https://en.wikipedia.org/wiki/Newtonian_fluid "Newtonian fluid") **·** [non-Newtonian](https://en.wikipedia.org/wiki/Non-Newtonian_fluid "Non-Newtonian fluid")) [Buoyancy](https://en.wikipedia.org/wiki/Buoyancy "Buoyancy") **·** [Mixing](https://en.wikipedia.org/wiki/Mixing_\(process_engineering\) "Mixing (process engineering)") **·** [Pressure](https://en.wikipedia.org/wiki/Fluid_pressure "Fluid pressure") |
| [Liquids](https://en.wikipedia.org/wiki/Liquid "Liquid") |
| [Adhesion](https://en.wikipedia.org/wiki/Adhesion "Adhesion") [Capillary action](https://en.wikipedia.org/wiki/Capillary_action "Capillary action") [Chromatography](https://en.wikipedia.org/wiki/Chromatography "Chromatography") [Cohesion (chemistry)](https://en.wikipedia.org/wiki/Cohesion_\(chemistry\) "Cohesion (chemistry)") [Surface tension](https://en.wikipedia.org/wiki/Surface_tension "Surface tension") |
| [Gases](https://en.wikipedia.org/wiki/Gas "Gas") |
| [Atmosphere](https://en.wikipedia.org/wiki/Atmosphere "Atmosphere") [Boyle's law](https://en.wikipedia.org/wiki/Boyle%27s_law "Boyle's law") [Charles's law](https://en.wikipedia.org/wiki/Charles%27s_law "Charles's law") [Combined gas law](https://en.wikipedia.org/wiki/Combined_gas_law "Combined gas law") [Fick's law](https://en.wikipedia.org/wiki/Fick%27s_law "Fick's law") [Gay-Lussac's law](https://en.wikipedia.org/wiki/Gay-Lussac%27s_law "Gay-Lussac's law") [Graham's law](https://en.wikipedia.org/wiki/Graham%27s_law "Graham's law") |
| [Plasma](https://en.wikipedia.org/wiki/Plasma_\(physics\) "Plasma (physics)") |
| |
| [Viscoelasticity](https://en.wikipedia.org/wiki/Viscoelasticity "Viscoelasticity") [Rheometry](https://en.wikipedia.org/wiki/Rheometry "Rheometry") [Rheometer](https://en.wikipedia.org/wiki/Rheometer "Rheometer") |
| [Smart fluids](https://en.wikipedia.org/wiki/Smart_fluid "Smart fluid") |
| [Electrorheological](https://en.wikipedia.org/wiki/Electrorheological_fluid "Electrorheological fluid") [Magnetorheological](https://en.wikipedia.org/wiki/Magnetorheological_fluid "Magnetorheological fluid") [Ferrofluids](https://en.wikipedia.org/wiki/Ferrofluid "Ferrofluid") |
| Scientists [Bernoulli](https://en.wikipedia.org/wiki/Daniel_Bernoulli "Daniel Bernoulli") [Boyle](https://en.wikipedia.org/wiki/Robert_Boyle "Robert Boyle") [Cauchy](https://en.wikipedia.org/wiki/Augustin-Louis_Cauchy "Augustin-Louis Cauchy") [Charles](https://en.wikipedia.org/wiki/Jacques_Charles "Jacques Charles") [Euler](https://en.wikipedia.org/wiki/Leonhard_Euler "Leonhard Euler") [Fick](https://en.wikipedia.org/wiki/Adolf_Eugen_Fick "Adolf Eugen Fick") [Gay-Lussac](https://en.wikipedia.org/wiki/Joseph_Louis_Gay-Lussac "Joseph Louis Gay-Lussac") [Graham](https://en.wikipedia.org/wiki/Thomas_Graham_\(chemist\) "Thomas Graham (chemist)") [Hooke](https://en.wikipedia.org/wiki/Robert_Hooke "Robert Hooke") [Newton](https://en.wikipedia.org/wiki/Isaac_Newton "Isaac Newton") [Navier](https://en.wikipedia.org/wiki/Claude-Louis_Navier "Claude-Louis Navier") [Noll](https://en.wikipedia.org/wiki/Walter_Noll "Walter Noll") [Pascal](https://en.wikipedia.org/wiki/Blaise_Pascal "Blaise Pascal") [Stokes](https://en.wikipedia.org/wiki/Sir_George_Stokes,_1st_Baronet "Sir George Stokes, 1st Baronet") [Truesdell](https://en.wikipedia.org/wiki/Clifford_Truesdell "Clifford Truesdell") |
| [v](https://en.wikipedia.org/wiki/Template:Continuum_mechanics "Template:Continuum mechanics") [t](https://en.wikipedia.org/wiki/Template_talk:Continuum_mechanics "Template talk:Continuum mechanics") [e](https://en.wikipedia.org/wiki/Special:EditPage/Template:Continuum_mechanics "Special:EditPage/Template:Continuum mechanics") |
**Hydrostatics** is the branch of [fluid mechanics](https://en.wikipedia.org/wiki/Fluid_mechanics "Fluid mechanics") that studies [fluids](https://en.wikipedia.org/wiki/Fluid "Fluid") at [hydrostatic equilibrium](https://en.wikipedia.org/wiki/Hydrostatic_equilibrium "Hydrostatic equilibrium")[\[1\]](https://en.wikipedia.org/wiki/Hydrostatics#cite_note-1) and "the pressure in a fluid or exerted by a fluid on an immersed body".[\[2\]](https://en.wikipedia.org/wiki/Hydrostatics#cite_note-MW_dictionary_def-2) The word "hydrostatics" is sometimes used to refer specifically to water and other liquids, but more often it includes both gases and liquids, whether [compressible](https://en.wikipedia.org/wiki/Compressible_flow "Compressible flow") or [incompressible](https://en.wikipedia.org/wiki/Incompressible_flow "Incompressible flow"). It encompasses the study of the conditions under which fluids are at rest in [stable equilibrium](https://en.wikipedia.org/wiki/Mechanical_equilibrium "Mechanical equilibrium"). It is opposed to *[fluid dynamics](https://en.wikipedia.org/wiki/Fluid_dynamics "Fluid dynamics")*, the study of fluids in motion.
Hydrostatics is fundamental to *[hydraulics](https://en.wikipedia.org/wiki/Hydraulics "Hydraulics")*, the [engineering](https://en.wikipedia.org/wiki/Engineering "Engineering") of equipment for storing, transporting and using fluids. It is also relevant to [geophysics](https://en.wikipedia.org/wiki/Geophysics "Geophysics") and [astrophysics](https://en.wikipedia.org/wiki/Astrophysics "Astrophysics") (for example, in understanding [plate tectonics](https://en.wikipedia.org/wiki/Plate_tectonics "Plate tectonics") and the anomalies of the [Earth's gravitational field](https://en.wikipedia.org/wiki/Gravity_of_Earth "Gravity of Earth")), to [meteorology](https://en.wikipedia.org/wiki/Meteorology "Meteorology"), to [medicine](https://en.wikipedia.org/wiki/Medicine "Medicine") (in the context of [blood pressure](https://en.wikipedia.org/wiki/Blood_pressure "Blood pressure")), and many other fields.
Hydrostatics offers physical explanations for many phenomena of everyday life, such as why [atmospheric pressure](https://en.wikipedia.org/wiki/Atmospheric_pressure "Atmospheric pressure") changes with [altitude](https://en.wikipedia.org/wiki/Altitude "Altitude"), why wood and oil float on water, and why the surface of still water is always [level](https://en.wikipedia.org/wiki/Water_level "Water level") according to the [curvature of the earth](https://en.wikipedia.org/wiki/Spherical_Earth "Spherical Earth").
## History
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=1 "Edit section: History")\]
Some principles of hydrostatics have been known in an empirical and intuitive sense since antiquity, by the builders of boats, [cisterns](https://en.wikipedia.org/wiki/Cistern "Cistern"), [aqueducts](https://en.wikipedia.org/wiki/Aqueduct_\(water_supply\) "Aqueduct (water supply)") and [fountains](https://en.wikipedia.org/wiki/Fountain "Fountain"). [Archimedes](https://en.wikipedia.org/wiki/Archimedes "Archimedes") is credited with the discovery of [Archimedes' Principle](https://en.wikipedia.org/wiki/Archimedes%27_Principle "Archimedes' Principle"), which relates the [buoyancy](https://en.wikipedia.org/wiki/Buoyancy "Buoyancy") force on an object that is submerged in a fluid to the weight of fluid displaced by the object. The [Roman](https://en.wikipedia.org/wiki/Roman_Empire "Roman Empire") engineer [Vitruvius](https://en.wikipedia.org/wiki/Vitruvius "Vitruvius") warned readers about [lead](https://en.wikipedia.org/wiki/Lead "Lead") pipes bursting under hydrostatic pressure.[\[3\]](https://en.wikipedia.org/wiki/Hydrostatics#cite_note-VitruviusVIII.6-3)
The concept of pressure and the way it is transmitted by fluids was formulated by the [French](https://en.wikipedia.org/wiki/France "France") [mathematician](https://en.wikipedia.org/wiki/Mathematician "Mathematician") and [philosopher](https://en.wikipedia.org/wiki/Philosopher "Philosopher") [Blaise Pascal](https://en.wikipedia.org/wiki/Blaise_Pascal "Blaise Pascal") in 1647.\[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")*\]
## Hydrostatics in ancient Greece and Rome
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=2 "Edit section: Hydrostatics in ancient Greece and Rome")\]
### Pythagorean Cup
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=3 "Edit section: Pythagorean Cup")\]
Main article: [Pythagorean cup](https://en.wikipedia.org/wiki/Pythagorean_cup "Pythagorean cup")
The "fair cup" or [Pythagorean cup](https://en.wikipedia.org/wiki/Pythagorean_cup "Pythagorean cup"), which dates from about the 6th century BC, is a hydraulic technology whose invention is credited to the Greek mathematician and geometer Pythagoras. It was used as a learning tool.\[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")*\]
The cup consists of a line carved into the interior of the cup, and a small vertical pipe in the center of the cup that leads to the bottom. The height of this pipe is the same as the line carved into the interior of the cup. The cup may be filled to the line without any fluid passing into the pipe in the center of the cup. However, when the amount of fluid exceeds this fill line, fluid will overflow into the pipe in the center of the cup. Due to the drag that molecules exert on one another, the cup will be emptied.
### Heron's fountain
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=4 "Edit section: Heron's fountain")\]
Main article: [Heron's fountain](https://en.wikipedia.org/wiki/Heron%27s_fountain "Heron's fountain")
[Heron's fountain](https://en.wikipedia.org/wiki/Heron%27s_fountain "Heron's fountain") is a device invented by [Heron of Alexandria](https://en.wikipedia.org/wiki/Heron_of_Alexandria "Heron of Alexandria") that consists of a jet of fluid being fed by a reservoir of fluid. The fountain is constructed in such a way that the height of the jet exceeds the height of the fluid in the reservoir, apparently in violation of principles of hydrostatic pressure. The device consisted of an opening and two containers arranged one above the other. The intermediate pot, which was sealed, was filled with fluid, and several [cannula](https://en.wikipedia.org/wiki/Cannula "Cannula") (a small tube for transferring fluid between vessels) connecting the various vessels. Trapped air inside the vessels induces a jet of water out of a nozzle, emptying all water from the intermediate reservoir.\[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")*\]
## Pascal's contribution in hydrostatics
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=5 "Edit section: Pascal's contribution in hydrostatics")\]
Main article: [Pascal's law](https://en.wikipedia.org/wiki/Pascal%27s_law "Pascal's law")
Pascal made contributions to developments in both hydrostatics and hydrodynamics. [Pascal's law](https://en.wikipedia.org/wiki/Pascal%27s_law "Pascal's law") is a fundamental principle of fluid mechanics that states that any pressure applied to the surface of a fluid is transmitted uniformly throughout the fluid in all directions, in such a way that initial variations in pressure are not changed.
## Liquids (fluids with free surfaces)
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=6 "Edit section: Liquids (fluids with free surfaces)")\]
Liquids can have [free surfaces](https://en.wikipedia.org/wiki/Free_surface "Free surface") at which they interface with gases, or with a [vacuum](https://en.wikipedia.org/wiki/Vacuum "Vacuum"). In general, the lack of the ability to sustain a [shear stress](https://en.wikipedia.org/wiki/Shear_stress "Shear stress") entails that free surfaces rapidly adjust towards an equilibrium. However, on small length scales, there is an important balancing force from [surface tension](https://en.wikipedia.org/wiki/Surface_tension "Surface tension").
### Capillary action
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=7 "Edit section: Capillary action")\]
When liquids are constrained in vessels whose dimensions are small, compared to the relevant length scales, [surface tension](https://en.wikipedia.org/wiki/Surface_tension "Surface tension") effects become important leading to the formation of a [meniscus](https://en.wikipedia.org/wiki/Meniscus_\(liquid\) "Meniscus (liquid)") through [capillary action](https://en.wikipedia.org/wiki/Capillary_action "Capillary action"). This capillary action has profound consequences for biological systems as it is part of one of the two driving mechanisms of the flow of water in [plant](https://en.wikipedia.org/wiki/Plant "Plant") [xylem](https://en.wikipedia.org/wiki/Xylem "Xylem"), the [transpirational pull](https://en.wikipedia.org/wiki/Transpirational_pull "Transpirational pull").
### Hanging drops
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=8 "Edit section: Hanging drops")\]
Without surface tension, [drops](https://en.wikipedia.org/wiki/Drop_\(liquid\) "Drop (liquid)") would not be able to form. The dimensions and stability of drops are determined by surface tension. The drop's surface tension is directly proportional to the cohesion property of the fluid.
## See also
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=9 "Edit section: See also")\]
- [Communicating vessels](https://en.wikipedia.org/wiki/Communicating_vessels "Communicating vessels") – Set of internally connected containers containing a homogeneous fluid
- [D-DIA](https://en.wikipedia.org/wiki/D-DIA "D-DIA") – Apparatus used for high pressure and high temperature deformation experiments
- [Hydrostatic pressure](https://en.wikipedia.org/wiki/Hydrostatic_pressure "Hydrostatic pressure") – Physical quantity
- [Hydrostatic test](https://en.wikipedia.org/wiki/Hydrostatic_test "Hydrostatic test") – Non-destructive test of pressure vessels
- [Triaxial shear test](https://en.wikipedia.org/wiki/Triaxial_shear_test "Triaxial shear test") – Stress test with different levels of stress in each perpendicular direction
## References
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=10 "Edit section: References")\]
1. **[^](https://en.wikipedia.org/wiki/Hydrostatics#cite_ref-1)**
["Fluid Mechanics/Fluid Statics/Fundamentals of Fluid Statics - Wikibooks, open books for an open world"](https://en.wikibooks.org/wiki/Fluid_Mechanics/Fluid_Statics/Fundamentals_of_Fluid_Statics#Hydrostatic_Equilibrium). *en.wikibooks.org*. Retrieved 2021-04-01.
2. **[^](https://en.wikipedia.org/wiki/Hydrostatics#cite_ref-MW_dictionary_def_2-0)**
["Hydrostatics"](https://www.merriam-webster.com/dictionary/hydrostatics). *Merriam-Webster*. Retrieved 11 September 2018.
3. **[^](https://en.wikipedia.org/wiki/Hydrostatics#cite_ref-VitruviusVIII.6_3-0)** Marcus Vitruvius Pollio (ca. 15 BCE), ["The Ten Books of Architecture"](https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Vitruvius/8*.html), Book VIII, Chapter 6. At the University of Chicago's Penelope site. Accessed on 2013-02-25.
## Further reading
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=11 "Edit section: Further reading")\]
- Batchelor, George K. (1967). *An Introduction to Fluid Dynamics*. Cambridge University Press. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[0-521-66396-2](https://en.wikipedia.org/wiki/Special:BookSources/0-521-66396-2 "Special:BookSources/0-521-66396-2")
.
- Falkovich, Gregory (2011). *Fluid Mechanics (A short course for physicists)*. Cambridge University Press. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[978-1-107-00575-4](https://en.wikipedia.org/wiki/Special:BookSources/978-1-107-00575-4 "Special:BookSources/978-1-107-00575-4")
.
- Kundu, Pijush K.; Cohen, Ira M. (2008). *Fluid Mechanics* (4th rev. ed.). Academic Press. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[978-0-12-373735-9](https://en.wikipedia.org/wiki/Special:BookSources/978-0-12-373735-9 "Special:BookSources/978-0-12-373735-9")
.
- Currie, I. G. (1974). *Fundamental Mechanics of Fluids*. McGraw-Hill. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[0-07-015000-1](https://en.wikipedia.org/wiki/Special:BookSources/0-07-015000-1 "Special:BookSources/0-07-015000-1")
.
- Massey, B.; Ward-Smith, J. (2005). *Mechanics of Fluids* (8th ed.). Taylor & Francis. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[978-0-415-36206-1](https://en.wikipedia.org/wiki/Special:BookSources/978-0-415-36206-1 "Special:BookSources/978-0-415-36206-1")
.
- White, Frank M. (2003). *Fluid Mechanics*. McGraw–Hill. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[0-07-240217-2](https://en.wikipedia.org/wiki/Special:BookSources/0-07-240217-2 "Special:BookSources/0-07-240217-2")
.
## External links
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=12 "Edit section: External links")\]
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Look up ***[hydrostatics](https://en.wiktionary.org/wiki/hydrostatics "wiktionary:hydrostatics")*** in Wiktionary, the free dictionary.
- [The Flow of Dry Water - The Feynman Lectures on Physics](https://www.feynmanlectures.caltech.edu/II_40.html)
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Hydrostatics
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| Readable Markdown | From Wikipedia, the free encyclopedia
[](https://en.wikipedia.org/wiki/File:Table_of_Hydraulics_and_Hydrostatics,_Cyclopaedia,_Volume_1.jpg)
Table of Hydraulics and Hydrostatics, from the 1728 *[Cyclopædia](https://en.wikipedia.org/wiki/Cyclop%C3%A6dia,_or_an_Universal_Dictionary_of_Arts_and_Sciences "Cyclopædia, or an Universal Dictionary of Arts and Sciences")*
**Hydrostatics** is the branch of [fluid mechanics](https://en.wikipedia.org/wiki/Fluid_mechanics "Fluid mechanics") that studies [fluids](https://en.wikipedia.org/wiki/Fluid "Fluid") at [hydrostatic equilibrium](https://en.wikipedia.org/wiki/Hydrostatic_equilibrium "Hydrostatic equilibrium")[\[1\]](https://en.wikipedia.org/wiki/Hydrostatics#cite_note-1) and "the pressure in a fluid or exerted by a fluid on an immersed body".[\[2\]](https://en.wikipedia.org/wiki/Hydrostatics#cite_note-MW_dictionary_def-2) The word "hydrostatics" is sometimes used to refer specifically to water and other liquids, but more often it includes both gases and liquids, whether [compressible](https://en.wikipedia.org/wiki/Compressible_flow "Compressible flow") or [incompressible](https://en.wikipedia.org/wiki/Incompressible_flow "Incompressible flow"). It encompasses the study of the conditions under which fluids are at rest in [stable equilibrium](https://en.wikipedia.org/wiki/Mechanical_equilibrium "Mechanical equilibrium"). It is opposed to *[fluid dynamics](https://en.wikipedia.org/wiki/Fluid_dynamics "Fluid dynamics")*, the study of fluids in motion.
Hydrostatics is fundamental to *[hydraulics](https://en.wikipedia.org/wiki/Hydraulics "Hydraulics")*, the [engineering](https://en.wikipedia.org/wiki/Engineering "Engineering") of equipment for storing, transporting and using fluids. It is also relevant to [geophysics](https://en.wikipedia.org/wiki/Geophysics "Geophysics") and [astrophysics](https://en.wikipedia.org/wiki/Astrophysics "Astrophysics") (for example, in understanding [plate tectonics](https://en.wikipedia.org/wiki/Plate_tectonics "Plate tectonics") and the anomalies of the [Earth's gravitational field](https://en.wikipedia.org/wiki/Gravity_of_Earth "Gravity of Earth")), to [meteorology](https://en.wikipedia.org/wiki/Meteorology "Meteorology"), to [medicine](https://en.wikipedia.org/wiki/Medicine "Medicine") (in the context of [blood pressure](https://en.wikipedia.org/wiki/Blood_pressure "Blood pressure")), and many other fields.
Hydrostatics offers physical explanations for many phenomena of everyday life, such as why [atmospheric pressure](https://en.wikipedia.org/wiki/Atmospheric_pressure "Atmospheric pressure") changes with [altitude](https://en.wikipedia.org/wiki/Altitude "Altitude"), why wood and oil float on water, and why the surface of still water is always [level](https://en.wikipedia.org/wiki/Water_level "Water level") according to the [curvature of the earth](https://en.wikipedia.org/wiki/Spherical_Earth "Spherical Earth").
Some principles of hydrostatics have been known in an empirical and intuitive sense since antiquity, by the builders of boats, [cisterns](https://en.wikipedia.org/wiki/Cistern "Cistern"), [aqueducts](https://en.wikipedia.org/wiki/Aqueduct_\(water_supply\) "Aqueduct (water supply)") and [fountains](https://en.wikipedia.org/wiki/Fountain "Fountain"). [Archimedes](https://en.wikipedia.org/wiki/Archimedes "Archimedes") is credited with the discovery of [Archimedes' Principle](https://en.wikipedia.org/wiki/Archimedes%27_Principle "Archimedes' Principle"), which relates the [buoyancy](https://en.wikipedia.org/wiki/Buoyancy "Buoyancy") force on an object that is submerged in a fluid to the weight of fluid displaced by the object. The [Roman](https://en.wikipedia.org/wiki/Roman_Empire "Roman Empire") engineer [Vitruvius](https://en.wikipedia.org/wiki/Vitruvius "Vitruvius") warned readers about [lead](https://en.wikipedia.org/wiki/Lead "Lead") pipes bursting under hydrostatic pressure.[\[3\]](https://en.wikipedia.org/wiki/Hydrostatics#cite_note-VitruviusVIII.6-3)
The concept of pressure and the way it is transmitted by fluids was formulated by the [French](https://en.wikipedia.org/wiki/France "France") [mathematician](https://en.wikipedia.org/wiki/Mathematician "Mathematician") and [philosopher](https://en.wikipedia.org/wiki/Philosopher "Philosopher") [Blaise Pascal](https://en.wikipedia.org/wiki/Blaise_Pascal "Blaise Pascal") in 1647.\[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")*\]
## Hydrostatics in ancient Greece and Rome
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=2 "Edit section: Hydrostatics in ancient Greece and Rome")\]
The "fair cup" or [Pythagorean cup](https://en.wikipedia.org/wiki/Pythagorean_cup "Pythagorean cup"), which dates from about the 6th century BC, is a hydraulic technology whose invention is credited to the Greek mathematician and geometer Pythagoras. It was used as a learning tool.\[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")*\]
The cup consists of a line carved into the interior of the cup, and a small vertical pipe in the center of the cup that leads to the bottom. The height of this pipe is the same as the line carved into the interior of the cup. The cup may be filled to the line without any fluid passing into the pipe in the center of the cup. However, when the amount of fluid exceeds this fill line, fluid will overflow into the pipe in the center of the cup. Due to the drag that molecules exert on one another, the cup will be emptied.
[Heron's fountain](https://en.wikipedia.org/wiki/Heron%27s_fountain "Heron's fountain") is a device invented by [Heron of Alexandria](https://en.wikipedia.org/wiki/Heron_of_Alexandria "Heron of Alexandria") that consists of a jet of fluid being fed by a reservoir of fluid. The fountain is constructed in such a way that the height of the jet exceeds the height of the fluid in the reservoir, apparently in violation of principles of hydrostatic pressure. The device consisted of an opening and two containers arranged one above the other. The intermediate pot, which was sealed, was filled with fluid, and several [cannula](https://en.wikipedia.org/wiki/Cannula "Cannula") (a small tube for transferring fluid between vessels) connecting the various vessels. Trapped air inside the vessels induces a jet of water out of a nozzle, emptying all water from the intermediate reservoir.\[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")*\]
## Pascal's contribution in hydrostatics
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=5 "Edit section: Pascal's contribution in hydrostatics")\]
Pascal made contributions to developments in both hydrostatics and hydrodynamics. [Pascal's law](https://en.wikipedia.org/wiki/Pascal%27s_law "Pascal's law") is a fundamental principle of fluid mechanics that states that any pressure applied to the surface of a fluid is transmitted uniformly throughout the fluid in all directions, in such a way that initial variations in pressure are not changed.
## Liquids (fluids with free surfaces)
\[[edit](https://en.wikipedia.org/w/index.php?title=Hydrostatics&action=edit§ion=6 "Edit section: Liquids (fluids with free surfaces)")\]
Liquids can have [free surfaces](https://en.wikipedia.org/wiki/Free_surface "Free surface") at which they interface with gases, or with a [vacuum](https://en.wikipedia.org/wiki/Vacuum "Vacuum"). In general, the lack of the ability to sustain a [shear stress](https://en.wikipedia.org/wiki/Shear_stress "Shear stress") entails that free surfaces rapidly adjust towards an equilibrium. However, on small length scales, there is an important balancing force from [surface tension](https://en.wikipedia.org/wiki/Surface_tension "Surface tension").
When liquids are constrained in vessels whose dimensions are small, compared to the relevant length scales, [surface tension](https://en.wikipedia.org/wiki/Surface_tension "Surface tension") effects become important leading to the formation of a [meniscus](https://en.wikipedia.org/wiki/Meniscus_\(liquid\) "Meniscus (liquid)") through [capillary action](https://en.wikipedia.org/wiki/Capillary_action "Capillary action"). This capillary action has profound consequences for biological systems as it is part of one of the two driving mechanisms of the flow of water in [plant](https://en.wikipedia.org/wiki/Plant "Plant") [xylem](https://en.wikipedia.org/wiki/Xylem "Xylem"), the [transpirational pull](https://en.wikipedia.org/wiki/Transpirational_pull "Transpirational pull").
Without surface tension, [drops](https://en.wikipedia.org/wiki/Drop_\(liquid\) "Drop (liquid)") would not be able to form. The dimensions and stability of drops are determined by surface tension. The drop's surface tension is directly proportional to the cohesion property of the fluid.
- [Communicating vessels](https://en.wikipedia.org/wiki/Communicating_vessels "Communicating vessels") – Set of internally connected containers containing a homogeneous fluid
- [D-DIA](https://en.wikipedia.org/wiki/D-DIA "D-DIA") – Apparatus used for high pressure and high temperature deformation experiments
- [Hydrostatic pressure](https://en.wikipedia.org/wiki/Hydrostatic_pressure "Hydrostatic pressure") – Physical quantity
- [Hydrostatic test](https://en.wikipedia.org/wiki/Hydrostatic_test "Hydrostatic test") – Non-destructive test of pressure vessels
- [Triaxial shear test](https://en.wikipedia.org/wiki/Triaxial_shear_test "Triaxial shear test") – Stress test with different levels of stress in each perpendicular direction
1. **[^](https://en.wikipedia.org/wiki/Hydrostatics#cite_ref-1)**
["Fluid Mechanics/Fluid Statics/Fundamentals of Fluid Statics - Wikibooks, open books for an open world"](https://en.wikibooks.org/wiki/Fluid_Mechanics/Fluid_Statics/Fundamentals_of_Fluid_Statics#Hydrostatic_Equilibrium). *en.wikibooks.org*. Retrieved 2021-04-01.
2. **[^](https://en.wikipedia.org/wiki/Hydrostatics#cite_ref-MW_dictionary_def_2-0)**
["Hydrostatics"](https://www.merriam-webster.com/dictionary/hydrostatics). *Merriam-Webster*. Retrieved 11 September 2018.
3. **[^](https://en.wikipedia.org/wiki/Hydrostatics#cite_ref-VitruviusVIII.6_3-0)** Marcus Vitruvius Pollio (ca. 15 BCE), ["The Ten Books of Architecture"](https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Vitruvius/8*.html), Book VIII, Chapter 6. At the University of Chicago's Penelope site. Accessed on 2013-02-25.
- Batchelor, George K. (1967). *An Introduction to Fluid Dynamics*. Cambridge University Press. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[0-521-66396-2](https://en.wikipedia.org/wiki/Special:BookSources/0-521-66396-2 "Special:BookSources/0-521-66396-2")
.
- Falkovich, Gregory (2011). *Fluid Mechanics (A short course for physicists)*. Cambridge University Press. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[978-1-107-00575-4](https://en.wikipedia.org/wiki/Special:BookSources/978-1-107-00575-4 "Special:BookSources/978-1-107-00575-4")
.
- Kundu, Pijush K.; Cohen, Ira M. (2008). *Fluid Mechanics* (4th rev. ed.). Academic Press. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[978-0-12-373735-9](https://en.wikipedia.org/wiki/Special:BookSources/978-0-12-373735-9 "Special:BookSources/978-0-12-373735-9")
.
- Currie, I. G. (1974). *Fundamental Mechanics of Fluids*. McGraw-Hill. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[0-07-015000-1](https://en.wikipedia.org/wiki/Special:BookSources/0-07-015000-1 "Special:BookSources/0-07-015000-1")
.
- Massey, B.; Ward-Smith, J. (2005). *Mechanics of Fluids* (8th ed.). Taylor & Francis. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[978-0-415-36206-1](https://en.wikipedia.org/wiki/Special:BookSources/978-0-415-36206-1 "Special:BookSources/978-0-415-36206-1")
.
- White, Frank M. (2003). *Fluid Mechanics*. McGraw–Hill. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)")
[0-07-240217-2](https://en.wikipedia.org/wiki/Special:BookSources/0-07-240217-2 "Special:BookSources/0-07-240217-2")
.
- [The Flow of Dry Water - The Feynman Lectures on Physics](https://www.feynmanlectures.caltech.edu/II_40.html) |
| Shard | 152 (laksa) |
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| Unparsed URL | org,wikipedia!en,/wiki/Hydrostatics s443 |