Question

Viscosity is a property of?

Answer 1

Viscosity is a property of fluids. 
It is a measure of the resistance of a fluid to flow or deform under an applied force or stress. Viscosity arises due to the internal friction between the different layers of fluid as they move relative to each other. 
Viscosity is observed in both liquids and gases, although its effects are more pronounced in liquids due to their greater intermolecular forces and closer packing of molecules. 
Viscosity depends on factors such as temperature, pressure, and the molecular structure of the fluid. It is typically measured in units such as poise or pascal-seconds (Pa·s) for liquids and poiseuille (Pa·s) or centipoise (cP) for gases.

Viscosity is a characteristic inherent to fluids. It encompasses the tendency of fluids to counteract the movement of particles within them. Notably, viscosity is notably influenced by alterations in temperature and pressure.

The viscosity of fluids primarily hinges on the intermolecular forces that exist between the constituent molecules or particles. As temperature escalates, the gap between particles enlarges, leading to a corresponding augmentation in fluid viscosity. Conversely, lowered temperatures contract intermolecular distances, causing a reduction in fluid viscosity.

Viscosity is accountable for endowing substances or materials with thickness. However, it's important to note that viscosity is not applicable to solids; it exclusively pertains to fluids such as liquids and gases.