Final answer:
A rotating viscometer is used to measure viscosity by analyzing the flow behavior of the liquid. This instrument consists of two concentric cylinders, and the time it takes for liquid to flow through a narrow tube or for steel balls to fall through the liquid is measured.
Step-by-step explanation:
A rotating viscometer is used to measure viscosity, which is a property of fluids that describes their resistance to flow. The instrument consists of two concentric cylinders, and the time it takes for a quantity of liquid to flow through a narrow vertical tube or for steel balls to fall through the liquid is measured. By analyzing the flow behavior, the viscosity of the liquid can be determined.