The term intrinsic viscosity refers to the property of a given liquid to resist flow due to internal friction. The greater the viscosity of a liquid, the more difficult it is to make that liquid flow. In the meter kilogram second (mks) system, viscosity has physical units of N x s / m^2, where N is the mks unit for force the newton. The more common unit for viscosity is the poise . The poise is part of the cgs (centimetre gram second) unit system (see reference 2). One poise equals a dyne x s / cm^2, where the dyne is the cgs unit of force.

Determine the liquid for which you want the viscosity in poise. As an example, convert the viscosity of standard motor oil to poise. In mks units the viscosity is 250 x 10^-3 N x s / m^2.

Convert from newtons to dynes. This is accomplished by multiplication by 10^5, since 1 N equals 10^5 dynes (See reference 3). Starting the example, you have ( 250 x 10^-3 N x s / m^2 ) x ( 10^5 dyne / N) which is 25,000 dyne x s / m^2.

Change square meters to square centimetres by dividing by 10^4 to get the viscosity in poise. This is because 1 square meter equals 10^4 square centimetres. (See References 3) Continuing the example, you have ( 25,000 dyne x s / m^2 ) x ( 1m^2 / 10^4cm^2 ) which is 2.5 dyne x s / cm^2, so the viscosity is 2.5 poise.

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