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What Happens if You Stir a Cup of Zero Viscosity Coffee?

Posted by LuLu on May 2, 2017 8:00:00 AM

In Applications, RheoSense, Inc., viscosity, Fun with Viscosity

First of all, the question is-- can there be a coffee or liquid with zero viscosity coffee?  We know that there is negative viscosity. Is having zero viscosity similar?

Viscosity is the resistance of a fluid to flow and it comes from the friction of molecules as they move against each other within the fluid. All fluids have at least some resistance to flow – except super fluids.

Superfluidity was originally discovered in liquid helium, by Pyotr Kapitsa and John F. Allen. At about minus-271 °C, the behavior of liquid helium turns surreal—it becomes bosons. It follows Bose-Einstein statistics and  under certain circumstances, they condense in the state that possess the least amount of energy (zero or negative).

This results are a few very unique properties of superfluid including infinite thermal conductivity. Any volume of super fluid, no matter how large, will always be precisely the same temperature throughout.

Theoretically, superfluid also approaches zero entropythe lowest possible energy that a quantum mechanical physical system can have. This means that if you stir a cup of zero viscosity coffee, it will swirl for almost forever. This indicates that if you drink a cup of zero viscosity coffee, it will also give you zero energy.