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Surface tension is the tendency of liquid surfaces at rest to minimize their surface area. 
Surface tension is a property of liquids that arises from the cohesive forces between their molecules. These forces cause the surface of a liquid to contract to the smallest possible area, creating a "skin" on the surface. This property allows objects denser than water to float on water, and water droplets to form a spherical shape. 
The attractive forces between molecules of the same substance are called cohesive forces.
Cohesive force is the attraction between molecules of the same substance, like water molecules attracting each other. It's the force that causes similar molecules to attract and stick together, resulting in properties such as surface tension and capillary action.