Dancing Raisins

Bodies immersed in gaseous fluids are natural sites for the nucleation of bubbles. These bubbles confer the bodies with additional buoyancy which can lift them upward against gravity. But a free-surface can clean the body of these lifting agents as the gas escapes which may result in plummeting, as the body begins the process anew. We characterize this system using experiments, simulations, and theory, showing periodic and aperiodic orbits across a wide range of fluids and body surface parameters. Body rotations at the surface are shown to play particularly important roles in both single- and multi-body systems, and a phase-change is observed at a critical volume fraction of particles. This tabletop-scale system may speak to related phenomena in biology (blood during decompression), engineering (oil extraction), and geophysics (supersaturated magma and volcanic eruptions).