Alberto Tufaile, a physicist at the University of São Paulo in Brazil, was studying bubble formation in a chamber of glycerol when he noticed something peculiar. "Suddenly, we started seeing strange bubbles that didn't rise and lasted an hour or more if they didn't touch bottom. We didn't know what they were," he says. He and his colleague, physicist Jose Carlos Sartorelli, found a partial answer on a Web site created by amateur bubblemakers. The mystery blobs were anti-bubbles, spheres of liquid suspended inside a shell of air. Intrigued, Tufaile and Sartorelli set out to make the first scientific study of these little-understood objects.
Photograph courtesy of Alberto Tufaile