One poise is the viscosity of a fluid that requires a shearing force of 1 dyne to move a square centimetre area of either of two parallel layers of fluid 1 centimetre apart with a velocity of 1 centimetre per second relative to the other layer, the space between the layers being filled with the fluid.

The dynamic viscosity η is a measure of the viscosity of a fluid. The higher the viscosity, the thicker the fluid; the lower the viscosity, the thinner it is.

Stocke's Law: Stocke's Law is a mathematical equation that expresses the settling velocities of the small spherical particles in a fluid medium, According to Stocke's Law,The force that retards a sphere moving through a viscous fluid is directly proportional to the velocity,and the radius of the sphere,and the viscosity of the fluid The force of viscosity on a small sphere is given by mathematically F = 6 πηrv where, F is the frictional force known as stocke's drag-acting on the interface between the fluid and the particle μ is the viscosity r is the radius of spherical object v is the flow velocity η is the constant known as coefficient of viscosity