Question

Why does surface tension act tangentially?

Answer 1

Hint: The tendency of a fluid surface to shrink into the minimum surface is called the surface tension. This phenomenon occurs when the surface of a liquid is in contact with another phase. Liquids always tend to acquire the minimum surface area possible. It can be defined as the surface force F to the length L along which the force acts.

Complete answer:
The surface tension acts tangentially usually when the net forces act downwards. This can be explained in the following.
Tensile force is generated when the particles on the interface are having equal forces. The net cohesive force acts downwards because the distance between the particles in the air is greater than the distance between the particles in the water. Also, this resultant net downward force on particles will not let the interface move further. Because even if one particle is sucked by then another particle will try and bounce back to take the missing particle’s position.

Note: Surface tension also depends upon the force of attraction of solid, liquid, or gas that is in contact with the liquid surface. It also depends upon the forces of attraction between the particles within the given liquid. Surface tension can be measured in terms of dynes/cm. There are various examples of surface tension that are found in nature. The most famous example is water striders. These insects can walk on water as their weight is considerably less and so that they cannot penetrate the surface of the water. Other examples include insects walking on water, a needle floating on the surface of the water and many more.