Number 34 (Story #2), May 15, 1991 by Phillip F. Schewe and Ben Stein SONOLUMINESCENCE is the conversion of sound energy into light energy. At a recent meeting of the Acoustical Society of America in Baltimore, Seth Putterman of UCLA described the most detailed study yet of this interesting effect. He observed 100 psec pulses of light emanating from small nitrogen bubbles trapped in a mixture of water and glycerine. The bubbles first absorb sound energy (from an applied 20-kHz field) and expand to a size of 100 microns; then they collapse to a size of a few microns, releasing light. Then the process begins again. Putterman considers the concentration of energy (the optical pulse being much briefer than the sound-wave cycle) to be a "spectacular phenomenon." (Science News, 11 May.)