Explain surface tension phenomenon with examples

Surface tension is the tendency of fluid surfaces to shrink into the minimum surface area possible. The surface tension can be determined by the difference of interactions between the molecules of the material (fluid) with the molecules of the material in contact.

What is Surface Tension?

The tendency of fluid surfaces to shrink into the minimum surface area possible is referred to as surface tension. Scientifically we can defined surface tension as the phenomenon that arises when the surface of a liquid is in contact with another phase (can be a liquid ). Liquids tend to occupy the least surface area possible. The surface of the liquid acts like an elastic sheet.

Why Surface tension?

It is a physical property of liquids, in which the molecules are drawn into each and every side. The intermolecular forces such as Van der Waals force, draw the liquid particles together. Throughout the surface, the particles are attracted to the rest of the liquid.

Unit and Formula

T=F/L
Where,
T is the surface tension of the liquid
F is the force per unit length
L is the length in which force act

The SI unit of Surface Tension is Newton per Meter or N/m or Nm-1.

The CGS unit of Surface Tension is Dyn per cm 0r Dyn/cm or Dyn cm-1.

Examples:

  • Floating needle on the surface of the water
  • Cleansing action of soap and detergents on clothes
  • Water droplets on some surfaces of the leaves. Droplets look like small bubbles
  • Rainproof or waterproof sheets or covering materials (that get rid of water)
  • Round bubbles where the surface tension of water provides the wall tension for the formation of water bubbles

Surface tension has a major contribution to the branch of physics. Many concepts, derivations, formulas have come up through this phenomenon. Surface tension plays an important role in understanding the properties of liquids, viscosity, and fluidity of the substance.

 

 

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