SCIENCE NON LINÉAIRE

In this image we see four steps of the partial coalescence of a soap bubble on a soap film. The bubble is gently deposited on the film. The film at the point of merger ruptures, so the high pressure air inside the bubble is evacuated. One might expect complete coalescence, that the surface would simply return to a planar configuration in order to minimize the overall surface area. Instead, capillary waves sweep up the bubble and initiate pinch-off, resulting in a smaller daughter bubble. The daughter bubble has approximately half the radius of its progenitor. The process repeats itself up to three times.