DEFINITION :
DEFINITION Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or extensional stress.
In general terms it is the resistance of a liquid to flow, or its "thickness".
The word "viscosity" derives from the Latin word "viscum"
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Viscosity describes a fluid's internal resistance to flow
All real fluids (except superfluids) have some resistance to stress, but a fluid which has no resistance to shear stress is known as an ideal fluid or inviscid fluid.
VISCOSITY COEFFICIENT :
VISCOSITY COEFFICIENT Dynamic viscosity
Kinematic viscosity
Volume viscosity (or bulk viscosity)
Shear viscosity
Extensional viscosity
DETERMINATION OF VISCOSITY :
DETERMINATION OF VISCOSITY delta p = difference in density between the sphere and the liquid
g = acceleration of gravity
a = radius of sphere
v = velocity = d/t = (distance sphere falls)/(time of it takes to fall)
VISCOSITY OF VARIOUS LIQUID :
VISCOSITY OF VARIOUS LIQUID Substance Viscosity (Pa s)
Air (at 18 oC) 1.9 x 10-5 (0.000019)
Water (at 20 oC) 1 x 10-3 (0.001)
Canola Oil at room temp. 0.1
Motor Oil at room temp. 1
Corn syrup at room temp. 8
Pahoehoe lava 100 to 1,000
A'a lava 1000 to 10,000
Andesite lava 106 to 107
Rhyolite lava 1011 to 1012
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MOISTURE
DEFINITION :
DEFINITION Moisture generally refers to the presence of water, often in trace amounts.
The moisture content is often an important aspect of various foodstuffs including cheese and many dried goods such as tea where excess moisture can promote bacterial growth, decay, molding, or rotting over time.
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Some foodstuffs and other packaged products come with desiccators, often made of silicon oxide, to absorb moisture.
Moisture is also sometimes used to refer to the liquid form of solvents other than water, especially when present in a solid.