Bubbles can be made to “gallop” across the roof of a liquid-filled container simply by shaking it up and down – a surprise discovery that could be exploited as a cleaning technique.

Pedro J. Sáenz at the University of North Carolina at Chapel Hill and his colleagues were studying the behaviour of waves in a sealed container using vibrations when they made a chance discovery. The team found that shaking the liquid-filled chamber up and down at particular frequencies caused a bubble that had mistakenly…