viscosity of water
Understanding Viscosity
Let us try to understand the meaning of the word viscosity , it refers to the quantity of internal resistance in the fluid or in simpler terms the stickiness within the fluid .
So a liquid that has more internal resistance is a viscous fluid as compared to some fluid that has lesser internal resistance.
An important point to note here is that viscosity is a relative concept,it does not have any absolute meaning.
Visualizing viscosity
Let us pour honey and water on a inclined plane, we see that clearly honey flows down
slowly as compared to water.
Did not get a better image representing the experiment ( Please manage with it!)
Thus we can conclude that honey is more viscous than water.
Classification
There are two types of viscosity :
a) Dynamic Viscosity
Unit : Pa sec
b) Kinematic Viscosity
Unit : m^2 / sec
Number Game
One thing to understand is that the viscosity of a fluid depends upon various properties , one of them being temperature . The Viscosity of any fluid changes with temperature .In the case of a liquid it decreases with increase in temperature and if you are looking at a gas then its viscosity increases with increase in temperature.
- At around 25°C [1] :
- Dynamic Viscosity = 0.89 m Pa sec
- Kinematic Viscosity = 0.8926 mm^2/sec
We can find standard values at different values online in some websites (but accept the values given at your own risk) or refer to some thermodynamic data handbook.
Static Viscosity: 8.9 x 10e-4 Pa·s at 25 °C.
Dynamic Viscosity: The one which varies temperature change.
It decreases with increase in temperature.
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