MadSci Network: Physics Query:

### Re: What are non-Newtonian fluids?

Area: Physics
Posted By: Steve Merideth, Secondary School Teacher Math/Physical Sciences, Russellville Middle School
Date: Wed Feb 19 18:00:39 1997
Message:

Newtonian fluids have a constant viscosity at a given temperature. Hence Non-Newtonian fluids have a variable viscosity at a constant temperature. The viscosity will vary with the rate of shear of the fluid. Shear rate is defined as the difference between velocity of parallel faces of a fluid element divided by the distances between the faces.

The Viscosity of a fluid is its resistance to flow. To put things in simpler terms, a single grade motor oil is an example of a Newtonian fluid. Its viscosity remains constant at a constant temperature. Multigrade motor oils are non-Newtonian fluids. The viscosity at a temperature is inversely proportional to the rate at which the piston is moving through the cylinder. With the corn starch and water suspension, you should find a different viscosity with respect to the amount of force applied to the balloon.

DEFINITIONS MAY BE FOUND AT THE FOLLOWING WEBSITE:
http://www.diagnetics.com/glossary.html

EXAMPLES:
Corn Starch Fluid at Fluid Mechanics Demonstrations.

Have a fun project!

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