Difference between Redwood and Saybolt Viscometer

Viscosity is the nature a fluid by virtue of which it resists its own flow. If we assume 'h' as the distance between the two layers of the fluid and 'n' as the difference in relative velocity then, the force required per unit area of the liquid to maintain this relative velocity can be given as,

F=nv/h

Where,

F= Force per unit area or coefficient of viscosity

As the temperature rises the coefficient of viscosity decreases.

Read: What is Electrical Contactor? How Does a Contactor Work?

The unit of viscosity is poise in CGS system and Newton second/square meter in the SI system.

Difference between Redwood and Saybolt Viscometer

The main differences between the Redwood viscometer and Saybolt viscometer can be tabulated as follows,

Sr. No.	Saybolt Viscometer	Redwood Viscometer
1	The experiment is held and a 60ml of oil is passed through a standard orifice. The total time duration is then noted.	In this experiment is held and a 50ml of oil is passed through a standard orifice. The total time duration is then noted.
2	A stopper is provided at the bottom of the tube for the liquid not to flow. It is released during the experiment.	The stopper is replaced with a ball valve and orifice.