Kenneth Suslick University of Illinois at Urbana-Champaign

CHE-0079124Like fireflies, bubbles trapped and energized by ultrasound emit light in a periodic rhythm. By holding a single bubble of gas in a standing acoustic wave and driving it into pulsations, sound energy is converted into light with clocklike regularity. At the same time, the intense energy is used to blow molecules apart.

Professor Ken Suslick and postdoctoral associate Yuri Didenko at the University of Illinois are the first to quantify these effects in a single bubble. Less than one millionth of the sound energy is converted into light. A thousand times more energy goes into the formation of atoms, molecular fragments and ions. The largest part of the sonic energy is converted into mechanical energy, causing shock waves and motion in the liquid surrounding the gas bubble.

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Double-click on icon above to play the Single Bubble Cavitation movie

“Movie:” a stroboscopic image of two cycles of a cavitating single bubble in a spherical acoustic field at 25 kHz. Each cycle is 50 microseconds long. The sonoluminescence and sonochemistry are generated at the minimum of the bubble collapse.