Fluidity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or extensional stress. In everyday terms (and for fluids only), viscosity is "thickness". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. For example, high-viscosity magma will create a tall, steep stratovolcano, because it cannot flow far before it cools, while low-viscosity lava will create a wide, shallow-sloped shield volcano. Put simply, the less viscous something is, the greater its ease of movement (fluidity). [1] All real fluids (except superfluids) have some resistance to stress, but a fluid which has no resistance to shear stress is known as an ideal fluid or inviscid fluid. The study of viscosity is known as rheology.
Etymology
The word "viscosity" derives from the Latin word "viscum" for mistletoe. A viscous glue was made from mistletoe berries and used for lime-twigs to catch birds.[2]
References
- Symon, Keith (1971). Mechanics (Third ed.). Addison-Wesley. ISBN 0-201-07392-7.
- The Online Etymology Dictionary
Additional reading
- Massey, B. S. (1983). Mechanics of Fluids (Fifth ed.). Van Nostrand Reinhold (UK). ISBN 0-442-30552-4.
External links
- Fluid Characteristics Chart A table of viscosities and vapor pressures for various fluids
- Gas Dynamics Toolbox Calculate coefficient of viscosity for mixtures of gases
- Glass Viscosity Measurement Viscosity measurement, viscosity units and fixpoints, glass viscosity calculation
- Kinematic Viscosity conversion between kinematic and dynamic viscosity.
- Physical Characteristics of Water A table of water viscosity as a function of temperature
- Project Trajectory Java Web Start Application for simulation of moving bodies through different and user definable media.
- Vogel–Tammann–Fulcher Equation Parameters
- Calculation of temperature-dependent dynamic viscosities for some common components
