Dynamic viscosity, also known as absolute viscosity, measures a fluid's internal resistance to flow when subjected to an external shear stress. In engineering, two units are frequently encountered: the Centipoise (cP) and the Pascal-second (Pa·s).
Centipoise (cP): A CGS (centimeter-gram-second) unit commonly used in industrial applications. It is defined as one-hundredth of a Poise. Water at 20°C has a viscosity of approximately 1 cP.
Pascal-second (Pa·s): The SI (International System of Units) derived unit for dynamic viscosity. It represents the viscosity of a fluid in which a stress of one Pascal produces a velocity gradient of one meter per second per meter.
The relationship between these units is defined by the conversion factor: \(1 \text{ cP} = 0.001 \text{ Pa·s}\). This conversion is essential when transitioning from legacy industrial specifications to modern SI-compliant engineering documentation.
Centipoise to Pascal-second Conversion Reference Table
Centipoise (cP)
Pascal-second (Pa·s)
0.1
1.0000e-04
0.5
5.0000e-04
1.0
0.001
2.0
0.002
5.0
0.005
10.0
0.01
20.0
0.02
50.0
0.05
100.0
0.1
500.0
0.5
1000.0
1
Conversion Example: 10 cP to Pa·s
To convert a value from Centipoise to Pascal-seconds, multiply the value by the conversion factor of 0.001.
The Centipoise remains prevalent because many common fluids, such as water, have a viscosity near 1 cP at room temperature. This makes cP a convenient, intuitive scale for engineers and technicians working in chemical processing and fluid dynamics.
Yes. Dynamic viscosity measures resistance to flow under force, while kinematic viscosity measures the resistive flow of a fluid under the influence of gravity. They are related by the fluid density: \(\nu = \frac{\mu}{\rho}\), where \(\nu\) is kinematic viscosity and \(\mu\) is dynamic viscosity.
"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison." "Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house." — Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)