Difference between revisions of "Viscosity"

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'''Definition'''
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'''Viscosity''' refers to the state or condition of being ''viscous''. It is measured as a physical property of a [[fluid]]. As a physical property, it determines the internal resistance of a fluid to flow. A fluid's viscosity is measured by determining its internal resistance to gradual deformation by shear forces or tensile stress.<sup>(1)</sup> Pitch, which is a dark viscous waxy material derived from [[tar]], may be the most viscous fluid and is an average 100 billion times as viscous as water.<sup>(1)</sup> The viscosity of a fluid is influenced by the following factors: molecular structure, external forces, and ambient conditions. The molecular structure of a fluid influences viscosity in a way that when the molecules are tightly linked, the higher is the resistance to deformation, and therefore it will have less tendency to flow. External forces such as shear forces or tensile stress act upon the fluid and therefore influence the flow of the fluid. The ambient conditions also affect viscosity. For instance, the viscosity of a fluid is lower when the temperature is higher. Therefore, a decreasing ambient temperature will increase the viscosity of a fluid.<sup>(2)</sup> In fluid dynamics, the term ''absolute viscosity'' (or ''dynamic viscosity'') refers to the force per unit area applied tangentially to a fluid, causing unit rate of displacement of parallel planes separated by a unit distance. Its units in cgs system: ''[[poise]]''. It can be determined through ''kinematic viscosity'' (also called ''momentum diffusivity''), i.e. the ratio of the absolute viscosity (''μ'') to the density of the fluid ''ρ''. Its units: ''stokes''.
  
''noun, plural: viscosities''
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== Related terms ==
 
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* [[Anomalous viscosity]]
(1) The state or condition of being [[viscous]]
 
 
 
(2) The physical property of a [[fluid]] that determines the internal resistance of a fluid to flow
 
 
 
 
'''Supplement'''
 
 
 
Viscosity is the state or condition of being [[viscous]]. It is measured as a physical property of a [[fluid]]. A fluid's viscosity is measured by determining its internal resistance to gradual deformation by shear forces or tensile stress.<sup>1</sup> Pitch, which is a dark viscous waxy material derived from [[tar]], may be the most viscous fluid and is an average 100 billion times as viscous as water.<sup>1</sup>
 
 
 
The viscosity of a fluid is influenced by the following factors: molecular structure, external forces, and ambient conditions. The molecular structure of a fluid influences viscosity in a way that when the molecules are tightly linked, the higher is the resistance to deformation, and therefore it will have less tendency to flow. External forces such as shear forces or tensile stress act upon the fluid and therefore influence the flow of the fluid. The ambient conditions also affect viscosity. For instance, the viscosity of a fluid is lower when the temperature is higher. Therefore, a decreasing ambient temperature will increase the viscosity of a fluid.<sup>2</sup>
 
 
 
 
 
''Word origin:'' Latin ''viscositas'', from Latin ''viscosus''
 
 
 
''See also:''
 
* [[shear]]
 
* [[fluid]]
 
''Related term(s):''
 
* [[viscous]] (''adjective'')
 
 
* [[Apparent viscosity]]
 
* [[Apparent viscosity]]
* [[Absolute viscosity]]
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* [[Blood viscosity]]
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* [[Kinematic viscosity]]
 
* [[Magnetic viscosity]]
 
* [[Magnetic viscosity]]
* [[Poiseuilles viscosity coefficient ]]
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* [[Poiseuilles viscosity coefficient]]
 
* [[Relative viscosity]]
 
* [[Relative viscosity]]
* [[Kinematic viscosity ]]
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* [[Anomalous viscosity ]]
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== See also ==
* [[Blood viscosity  ]]
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* [[Shear]]
''Mentioned in:''
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* [[Fluid]]
 
* [[Work of breathing ]]
 
* [[Work of breathing ]]
 
* [[Fluidity]]
 
* [[Fluidity]]
 
* [[Poiseuilles law]]
 
* [[Poiseuilles law]]
* [[Poise ]]
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* [[Viscance]]
* [[Viscance ]]
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== References ==
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# Hammonds, M. (2013). The World’s Slowest Experiment. AustralianScience.com.au. Retrieved from http://www.australianscience.com.au/science-2/the-worlds-slowest-experiment/
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# Factors Affecting Viscosity. (n.d.) Retrieved from http://www.viscopedia.com/basics/factors-affecting-viscometry/
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''Reference(s):''
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<br><sup>1</sup> Hammonds, M. (2013). The World’s Slowest Experiment. AustralianScience.com.au. Retrieved from http://www.australianscience.com.au/science-2/the-worlds-slowest-experiment/
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© Biology Online. Content provided and moderated by '''[https://www.biology-online.org/about/ Biology Online Editors]'''
<br><sup>2</sup> Factors Affecting Viscosity. (n.d.) Retrieved from http://www.viscopedia.com/basics/factors-affecting-viscometry/
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Latest revision as of 06:57, 20 October 2019

Viscosity refers to the state or condition of being viscous. It is measured as a physical property of a fluid. As a physical property, it determines the internal resistance of a fluid to flow. A fluid's viscosity is measured by determining its internal resistance to gradual deformation by shear forces or tensile stress.(1) Pitch, which is a dark viscous waxy material derived from tar, may be the most viscous fluid and is an average 100 billion times as viscous as water.(1) The viscosity of a fluid is influenced by the following factors: molecular structure, external forces, and ambient conditions. The molecular structure of a fluid influences viscosity in a way that when the molecules are tightly linked, the higher is the resistance to deformation, and therefore it will have less tendency to flow. External forces such as shear forces or tensile stress act upon the fluid and therefore influence the flow of the fluid. The ambient conditions also affect viscosity. For instance, the viscosity of a fluid is lower when the temperature is higher. Therefore, a decreasing ambient temperature will increase the viscosity of a fluid.(2) In fluid dynamics, the term absolute viscosity (or dynamic viscosity) refers to the force per unit area applied tangentially to a fluid, causing unit rate of displacement of parallel planes separated by a unit distance. Its units in cgs system: poise. It can be determined through kinematic viscosity (also called momentum diffusivity), i.e. the ratio of the absolute viscosity (μ) to the density of the fluid ρ. Its units: stokes.

Related terms

See also

References

  1. Hammonds, M. (2013). The World’s Slowest Experiment. AustralianScience.com.au. Retrieved from http://www.australianscience.com.au/science-2/the-worlds-slowest-experiment/
  2. Factors Affecting Viscosity. (n.d.) Retrieved from http://www.viscopedia.com/basics/factors-affecting-viscometry/



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