Poise (unit)

The poise (symbol P; ) is the unit of dynamic viscosity (absolute viscosity) in the centimetre–gram–second system of units (CGS). It is named after Jean Léonard Marie Poiseuille (see Hagen–Poiseuille equation). The centipoise (1 cP = 0.01 P) is more commonly used than the poise itself.

Dynamic viscosity has dimensions of , that is, .

The analogous unit in the International System of Units is the pascal-second (Pa⋅s):

The poise is often used with the metric prefix centi- because the viscosity of water at 20 Ã‚°C (standard conditions for temperature and pressure) is almost exactly 1 centipoise. A centipoise is one hundredth of a poise, or one millipascal-second (mPa⋅s) in SI units (1 cP = 10^{−3} Pa⋅s = 1 mPa⋅s).

The CGS symbol for the centipoise is cP. The abbreviations cps, cp, and cPs are sometimes seen.

Liquid water has a viscosity of 0.00890 P at 25 Ã‚°C at a pressure of 1 atmosphere (0.00890 P = 0.890 cP = 0.890 mPa⋅s).

See also

• Poiseuille (unit)
• Viscosity

References