The surface of a liquid behaves like a stretched elastic membrane (similar to a stretched rubber membrane) so as to possess minimum surface area. This weird nature of liquid is due to a phenomenon called surface tension.Surface Tension may be defined as the tensile force acting on the surface of a liquid when it is in contact with a gas or another surface with which it is immiscible.
The surface tension of a liquid can be varied by adding a solute to it. If inorganic salts (e.g: Sodium Chloride, Baking Soda) are added to a liquid, the surface tension of the liquid increases. If surfactants (e.g: soap, detergents) are added to a liquid, the surface tension decreases. Surface Tension is also dependent on temperature. In general, Surface Tension of a liquid decreases with increase in temperature.
The following are some of the illustrations of surface tension:
The surface tension of a liquid can be varied by adding a solute to it. If inorganic salts (e.g: Sodium Chloride, Baking Soda) are added to a liquid, the surface tension of the liquid increases. If surfactants (e.g: soap, detergents) are added to a liquid, the surface tension decreases. Surface Tension is also dependent on temperature. In general, Surface Tension of a liquid decreases with increase in temperature.
The following are some of the illustrations of surface tension:
- A water strider walks on the surface of water without getting immersed. This is because the surface of water behaves like a stretched elastic membrane and balances the weight of the water strider. You can see that in the picture below: (The impact of the weight of the water strider can be seen as depressions on the surface of water)
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