What is Surface tension?
Have you ever noticed that when you fill a glass up to the brim with water, you can still add a few more drops till it spills out? Or have you ever broken a thermometer and observed how the fallen mercury behaves?
This is where a property called surface tension comes into play. It is the tendency of liquids to acquire the least surface area possible. So what is surface tension? It is a phenomenon that occurs when the surface of a liquid is in contact with another phase (it can be a liquid as well). The surface of the liquid behaves like an elastic sheet.
Water at 100∘C has a surface tension value of 0.059 N/m and mercury has a surface tension value of 0.47 N/m.
If there is a small leaf or a paper clip placed on the surface of a glass of water, what causes it to float over it? The downward force of the body is balanced by the surface tension.
Surface Tension Formula:
It is expressed by the formula:
F is the force per unit length
L is the length in which force act
T is the surface tension of the liquid
Units of Surface Tension:
How to calculate Surface Tension:
Here is an example to calculate surface tension using the surface tension formula:
Question: Compute the surface tension of a given liquid whose dragging force is 7N and length in which the force acts is 2m?
F = 7N
L = 2m
According to the formula,
Stay tuned with Byju’s to learn more about surface tension, surface energy and much more.