Shown left is an artist's impression of the normal set-up for the generation of single-bubble sonoluminescence in a spherical flask full of water. Transducers are fixed to the glass and send vibrations through the assembly; thus shockwaves converge through the liquid towards the central (focal) point. When conditions are right, a glowing light is observed at that central position which is caused by the expansion and collapse of a sequence of tiny bubble events...