What happens to viscosity as the temperature increases?

Viscosity is a measure of a fluid's resistance to flow. As the temperature of a liquid increases, its viscosity generally decreases. This occurs because higher temperatures provide energy to the molecules in the fluid, causing them to move more vigorously. As the molecules gain energy and move more rapidly, they are better able to overcome the intermolecular forces that contribute to viscosity. As a result, the fluid becomes less viscous and flows more easily at elevated temperatures.

Understanding this relationship is vital in wastewater treatment processes, where the viscosity of sludges and other materials may affect pumping, mixing, and overall process efficiency.