Abstract: An experimental study of the evolution of two dimensional foam is presented. The topological properties of two-dimensional foam as a function of the evolution time were investigated, and the relationship between the topological properties and stability of two dimensional foam was discussed. In the evolution of two dimensional foam, two distincts tates were observed: a transients tate characterized by the presence of ordered state and a long-term fully disordered state. The long-term behavior of the foam shows that the average bubble area increases as a power law with exponent a =1.5, which is deviated from Von Neumann law and the possible reasons discussed. In addition, the distribution of sides of bubbles and the second moment of the distribution of number of sides are also discussed.

Key words: Two-dimensional foam, Topological property, Von Neumann law