What is the variations between viscosity and surface tension of an ideal fluid?

Compared to viscosity, surface tension is a simpler phenomenon. It is basically stable, changed mostly by temperature and chemicals that modify the bonding characteristics of the molecules. As temperature decreases, surface tension increases. The effects of adding an unrelated substance is illustrated by the example of putting soap (a surfactant) in water to reduce the surface tension, which allows the dirt on your hands to more easily mix with the water.