Soap film oscillations

One can bring a soap film into oscillations e.g. by shaking the wire frame. There are many possible ways of oscillation (modes) that are described by Bessel functions in the case of a circular membrane. The photos show some of the lowest frequency modes. The oscillations are caused by surface tension that, when we deform the membrane, forces the membrane to return to its original planar shape for which the total surface is the least. Due to what physicists call degeneracy, there exist even modes that "run around" the circle, such as the one in the first picture on the last line. Notice also the second picture on the second line that shows the film in the middle of breakage process.