Is Viscosity Present in Gasses?

  • Thread starter TriKri
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In summary, gases do have viscosity and the viscosity for normal air can be found in a table. Like liquid, gas also has viscosity, but the temperature-viscosity relationship is opposite for gas compared to liquid. This is due to momentum transfer between molecules in the gas. Sutherland's formula can be used to calculate a gas's viscosity based on temperature. The viscosity of a gas is also affected by pressure.
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TriKri
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Fluids have viscosity, but do gasses have it? And in that case, what is the viscosity for normal air (I know air isn't one gas)?
 
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Like liquid, gas has viscosity of course. But only one thing they are different is for liquid, the higher the temperature, the lower the viscosity and for gas, it's opposite.
 
  • #4
pixel01 said:
Like liquid, gas has viscosity of course. But only one thing they are different is for liquid, the higher the temperature, the lower the viscosity and for gas, it's opposite.

I don't doubt that you are correct, but could you or someone explain this to me?
 
  • #5
Archosaur said:
I don't doubt that you are correct, but could you or someone explain this to me?
It is correct. It has to do with momentum transfer between molecules in the gas. Look up Sutherland's formula to see how to calculate a gases viscosity based on temperature.
 
  • #6
pixel01 said:
Like liquid, gas has viscosity of course. But only one thing they are different is for liquid, the higher the temperature, the lower the viscosity and for gas, it's opposite.

I guess that is under a constant pressure, otherwise the viscosity is dependent on the pressure, isn't it?
 

1. What is viscosity?

Viscosity is a measure of a fluid's resistance to flow. It is a property of liquids and gases that describes how easily they can be deformed or moved by an external force.

2. Do all gasses have viscosity?

Yes, all gasses have viscosity, although the level of viscosity may vary. In general, gasses with a higher molecular weight have a higher viscosity.

3. How is viscosity measured?

Viscosity is typically measured using a viscometer, which is a device that determines the force required to move a fluid at a certain rate. The unit of measurement for viscosity is the poise (P) or centipoise (cP).

4. What factors affect the viscosity of gasses?

The viscosity of gasses is affected by temperature, pressure, and molecular weight. Generally, higher temperatures and pressures result in lower viscosity, while higher molecular weights result in higher viscosity.

5. Is viscosity important in everyday life?

Yes, viscosity plays a crucial role in our daily lives. For example, it affects the performance of engine oils, the flow of blood in our bodies, and the spread of pollutants in the atmosphere. Understanding the viscosity of gasses is also important in industrial processes and scientific research.

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