The dynamics of a topological change in a system of soap films

The study of soap films spanning wire frames continues to provide insight into both static and dynamic properties of foams. Experiments show that sufficiently small triangular faces shrink spontaneously, with their area varying with time as t^0.8. The growth of the Plateau border that emerges after the collapse of the triangular face is initially linear, followed by an oscillatory relaxation to the equilibrium length. Its initial growth rate decreases with the viscosity of the liquid. We also consider wire frames in the shape of n-sided prisms with regular polygonal ends, n ≥ 3, and employ experiments and computer simulations to examine the stability of soap film configurations within them. Spontaneous shrinking of small faces occurs in four and five-sided prismoidal frames, while this instability is suppressed for n ≥ 6.