E-Mail IMAGE: An initial crack in a film creates a RVPB (a). A second crack event in the film (b) causes a "collapse front " to be formed which sweeps up the RVPB... view more Credit: Tokyo Metropolitan University Tokyo, Japan - Researchers from Tokyo Metropolitan University have revealed how liquid foams collapse by observing individual collapse "events" with high-speed video microscopy. They found that cracks in films led to a receding liquid front which sweeps up the original film border, inverts its shape, and releases a droplet which hits and breaks other films. Their observations and physical model provide key insights into how to make foams more or less resistant to collapse.