Liquids tend to minimize their surface area because molecules of the liquid at the Surface experience net attractive force towards the interior of the liquid, this characteristic property of the liquid is known as surface tension. In general, surface tension decreases when temperature increases because cohesive forces decrease with an increase of molecular thermal activity. Increase in temperature increases the kinetic energy of the molecules and effectiveness of intermolecular attraction decreases, so surface tension decreases as the temperature is raised.
