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.

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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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