ABSTRACT
The instruments for viscosity measurements are designed to determine "a fluid's resistance to flow," a fluid property defined above as viscosity. The principle of the viscometers is similar to glass capillary viscometers, except that the flow through a short capillary does not satisfy or even approximate the Hagen-Poiseuille, fully developed, pipe flow. However, these viscometers are not suitable for absolute viscosity measurement, nor for non-Newtonian fluids. The falling sphere viscometer is one of the earliest and least involved methods to determine the absolute shear viscosity of a Newtonian fluid. The falling cylinder method is similar in concept to the falling sphere method except that a flat-ended, solid circular cylinder freely falls vertically in the direction of its longitudinal axis through a liquid sample within a cylindrical container.
