Poise (unit)

The poise (symbol P, /ˈpɔɪz/) is the unit of dynamic viscosity in the centimetre gram second system of units.^[1] It is named after Jean Léonard Marie Poiseuille.

1\ {\mbox{P}}=0.100\ {\mbox{kg}}\cdot {\mbox{m}}^{-1}\cdot {\mbox{s}}^{-1}=1\ {\mbox{g}}\cdot {\mbox{cm}}^{-1}\cdot {\mbox{s}}^{-1}

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

1\ {\mbox{Pa}}\cdot {\mbox{s}}=1\ {\mbox{kg}}\cdot {\mbox{m}}^{-1}\cdot {\mbox{s}}^{-1}=10\ {\mbox{P}}

The poise is often used with the metric prefix centi- because the viscosity of water at 20°C is almost exactly 1 centipoise. A centipoise is one one-hundredth of a poise, and one millipascal-second (mPa·s) in SI units. (1 cP = 10⁻³ Pa·s = 1 mPa·s)

The centipoise is properly abbreviated cP, but the alternative abbreviations cps, cp, and cPs are also commonly seen.

Water has a viscosity of 0.000899 poise at 25 °C and a pressure of 1 atmosphere. (0.000899 P = 0.899cP = 0.899 mPa·s) ^[2]

References

^ Gooch, Jan W. (2010). Encyclopedia dictionary of polymers (2nd ed.). Berlin: Springer. ISBN 978-1-4419-6246-1.
^ "Viscosity of Liquids", in CRC Handbook of Chemistry and Physics, 89th Edition (Internet Version 2009), David R. Lide, ed., CRC Press/Taylor and Francis, Boca Raton, FL.

[1] Gooch, Jan W. (2010). Encyclopedia dictionary of polymers (2nd ed.). Berlin: Springer. ISBN 978-1-4419-6246-1.

[2] "Viscosity of Liquids", in CRC Handbook of Chemistry and Physics, 89th Edition (Internet Version 2009), David R. Lide, ed., CRC Press/Taylor and Francis, Boca Raton, FL.

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See also

References