Answer
Surface tension is the effect of intermolecular forces on the surface of the liquid that tends to form a film.
Work Step by Step
As the strength of the intermolecular forces increase, the surface tension also increases and forms a stronger sort of film at the top since the molecules are being attracted/held together with more strength. As the temperature, or average kinetic energy of the molecules increases, then the surface tension decreases because the energy in these molecules goes towards loosening the forces between them.
