Active bubbles hold potential in fields ranging from water purification to medicine. Researchers can generate microbubbles by exposing liquids to high-intensity ultrasonic waves, a process known as sonication, and these energy waves heat up and pressurize the bubbles. For example, when bubbles in water are adiabatically collapsed by ultrasonic waves, the temperature inside the bubbles reaches more than several thousand degrees and the pressure several hundred atmospheres.