Sound can actually light up a liquid, an effect called sonoluminescence. The effect occurs when the power of an ultrasonic sound wave is transferred into liquid, superheating it and creating a very tiny bubble–the temperature inside is often hot enough to melt steel. The bubble suddenly implodes, transforming the heat energy into a very small flash of light. Scientists can produce this easily in the lab, but even some animals can do it. For example, the pistol shrimp stuns or kills its prey by producing a very brief 200 dB sound wave with a sharp, fast snap of its claw. While the light is too faint to be seen by the human eye, the effect creates sonoluminescence in the water around it.
[image by Dmitry Gelfand, Courtesy PortablePalace]