Electrolysis-assisted single-bubble sonoluminescence

Seeds for sonoluminescing single bubbles of hydrogen were created by direct-current electrolysis in 0.1 mole/L-aqueous solutions of potassium nitride. Sonolumnescence could be turned on and off by the alternate switching of electrolysis and sonication. The electrodes were copper wires and/or platinum wires of diameter 0.5 or 1.0 mm. A video microscope was used for observing the behavior of the bubbles that were emerging on the surface. Hydrogen bubbles required higher acoustic pressures than air bubbles to maintain the similar brightness.