8.1 surface tension 1.2 Micro-mechanism of surface tension o move molecules toward the surface, i.e., enlarge the surface area, energy must be expended o∝dA Surface area enlargement SW= odA The energy of a molecule at the surface is higher than that in the interiorThe energy of a molecule at the surface is higher than that in the interior Surface area enlargement To move molecules toward the surface, i.e., enlarge the surface area, energy must be expended. −W' dA −W' = dA 1.2 Micro-mechanism of surface tension 8.1 surface tension