A
viscometer (also called
viscosimeter) is an instrument used to measure the
viscosity and flow parameters of a
fluid. The common Brookfield-type viscometer determines the required force for rotating a disk in the fluid at known speed. Other viscometer types use
bubbles[?], balls or other objects. Viscometers that can measure fluids with high viscosity or molten polymers are usually called
rheometer[?] or
plastometer.