Viscosity

Most people are familiar with the term viscosity in the context of motor oil for their car. The viscosity grade for example, 5W 30 tells you the oil's thickness, or viscosity. There are a large variety of methods for measuring viscosity, mostly dependent on the range of the viscosity itself and the material being studied. The viscosity of air and water are by far the two most important materials for aviation aerodynamics and shipping fluid dynamics. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. Viscosity is an internal property of a fluid that offers resistance to flow. Viscometers are instruments designed to measure viscosity.