Quote:
Originally posted by myv65
*sigh* Nothing is ever as cut and dried as you would like. There are two measures of viscosity, dynamic (absolute) and kinematic. The difference between the two is inclusion or exclusion of the material's density. In dynamic terms, the viscosity of mercury and water isn't so different and if water didn't freeze they would be equal at ~ -5 to -10°C. In kinematic terms, mercury's density makes its viscosity much, much lower than water's.
IIRC, its the absolute viscosity that goes into calculating pump flow rates, but don't quote me on that one.
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Yeah... I remember seeing an experiment on PBS where they mixed something like corn starch, or some other kitchen product, and they showed that it looked really liquid, almost like water, but then the guy puts his hand in it, and quickly lifts the plate (an alu pie plate) and them slams it right back down. The plate followed the movement perfectly.
He was demonstrating that the viscosity changes, so I guess that's an example of dynamic (absolute) viscosity, versus kinematic viscosity. Sound about right, myv65?
(In this case though, I think the guy was demonstrating that some kind of starch has a low dynamic viscosity, but a high kinematic viscosity)