What is surface tension ?

Surface tensionis a contractive tendency of the surface of aliquidthat allows it to resist an external force. Surface tension is an important property that markedly influences the ecosystem. Surface tension is exposed, for example, any time an object or insect (e.g.water striders) that is denser than water is able to float or run along the water surface. At liquid-air interfaces, surface tension results from the greater attraction of water molecules to each other (due tocohesion) than to the molecules in the air (due toadhesion). The net effect is an inward force at its surface that causes water to behave as if its surface were covered with a stretched elastic membrane. Because of the relatively high attraction of water molecules for each other, water has a high surface tension (72.8 millinewtons per meter at 20°C) compared to that of most other liquids. Surface tension is an important factor in the phenomenon ofcapillarity.