Kinematic: A sample is placed in a "U" tube viscometer and the time taken for it to flow through the viscometer is noted. This is then converted to the viscosity.
Absolute: The time taken for a sphere of known dimensions to fall a known distance through the oil can be converted to the viscosity. Many other methods are also available, eg Redwood, flow cups, Churchill, cone & plate, Brookfield.
||Kinematic: BS 188
Absolute: BS 188
1 stoke = 1 x 10-4 m2/s
1 poise = 0.1 PaS
|Significance of result
|Oil viscosity is important to varnish, ink and paint formulators.
||In general kinematic viscosity is determined for low viscosity oils, whilst absolute viscosity is used for higher ones. Viscosities are usually carried out at 25°C but may be performed at other temperatures.
The test temperature and method must be quoted.
Viscosity decreases with increasing temperature.