[′van dər ‚wȯlz ′sər·fəs ‚ten·chən ‚fȯr·myə·lə] (thermodynamics) An empirical formula for the dependence of the surface tension on temperature: γ = Kpc⅔Tc⅓(1 -T/Tc)n, where γ is the surface tension, T is the temperature, Tcand pcare the critical temperature and pressure, K is a constant, and n is a constant equal to approximately 1.23.