Foster K R, Finch E D
Science. 1974 Jul 19;185(4147):256-8. doi: 10.1126/science.185.4147.256.
Acoustic transients can be thermally generated in water by pulsed microwave energy. The peak pressure level of these transients, measured within the audible frequency band as a function of the microwave pulse parameters, is adequate to explain the "clicks" heard by people exposed to microwave radiation.