Viscosity is defined as the ‘resistance to flow’ of a liquid or a gas.It is a property produced from collisions between adjacent particles in a fluid that are moving at different velocities.
For example, honey has a much complex viscosity than water.
The viscous forces that arise throughout fluid flow must not be jumbled with the elastic forces that arise in a solid in response to shear, compression or extension stresses.The viscosity of a fluid is an gesture of its fluidity. “thick” fluids such as heavy oils, are accepted as those having high viscosity.Water, cooking oils, coffee, and tea have low viscosities. Air is a fluid with very low viscosity.