Robert E. Apfel
Ctr. for Ultrasonics and Sonics, Yale Univ., New Haven, CT 06520-8286
Bubbles intrigue and amuse young and old, scientist and nonscientist, alike. When acoustical waves either cause or enhance the activity of bubbles, a variety of phenomena can be observed, ranging from sonoluminescence to ultrasonic cleaning, and from acoustical attenuation in the ocean to microbubble formation in blood. This tutorial will review these and other phenomena associated with acoustic cavitation, focusing on the interesting basic questions underlying the observations and summarizing the nature of the beneficial applications that cavitation permits and the strategies for avoiding undesirable cavitation. In addition, points of contact will be made with other bubble phenomena, such as boiling, hydrodynamic cavitation, decompression sickness, and radiation-induced bubble formation in superheated liquids (the bubble chamber). Participants in this tutorial should be able to tell if the glass of beer they are drinking from is clean. (If possible, samples will be available...for testing purposes.)