Fifteen years after Gibbs, J.D. van der Waals developed the theory of capillarity effects based on the hypothesis of a continuous variation of density. He added to the energy density the term formula_31 where "c" is the capillarity coefficient and "ρ" is the density. For the multiphase "equilibria", the results of the van der Waals approach practically coincide with the Gibbs formulae, but for modelling of the "dynamics" of phase transitions the van der Waals approach is much more convenient. The van der Waals capillarity energy is now widely used in the phase field models of multiphase flows. Such terms are also discovered in the dynamics of non-equilibrium gases.