Viscosity is the resistance of a liquid to flow, often associated with its thickness. It determines how easily liquids like honey, water, or oil move. Measured in poise or centipoise, viscosity is essential in industries like food processing, pharmaceuticals, and lubrication, as it affects everything from the ease of pouring liquids to the design of machinery.
- Pascal Second (Pa·s): The SI unit for dynamic viscosity, used to measure resistance to flow in fluids. For example, honey has a high viscosity of around 10 Pa·s, indicating a slower flow, while water has a lower viscosity of approximately 0.001 Pa·s.
- Poise (P): A unit in the centimeter-gram-second (CGS) system for measuring dynamic viscosity, where 1 poise equals 0.1 Pascal seconds. It’s named after the French physicist Jean Léonard Marie Poiseuille.
- Centipoise (cP): A common viscosity unit in various industries, especially in chemistry and biology. Water has a viscosity of about 1 centipoise, making it a useful reference point.
- Stokes (St): A CGS unit for measuring kinematic viscosity, where 1 stoke equals 1 cm²/s. Named after physicist George Gabriel Stokes, this unit is often used in fluid dynamics.
- Centistokes (cSt): A smaller unit of kinematic viscosity, commonly used for motor oil and other industrial fluids, where 1 centistoke equals 0.01 stokes. For example, engine oils may have viscosities ranging from 10 to 100 centistokes depending on their grade and temperature.
