Mathematics of Popping Bubbles in a Foam

Written By Robert Sanders Bubble baths and soapy dishwater, the refreshing head on a beer and the luscious froth on a cappuccino. All are foams, beautiful yet ephemeral as the bubbles pop one by one. Now, two researchers from the Department of Energy's (DOE's) Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley have described mathematically the successive stages in the complex evolution and disappearance of foamy bubbles, a feat that could help in modeling industrial processes in which liquids mix or in the formation of solid foams such as those used to cushion bicycle helmets. Applying these equations, they used supercomputers at DOE's National Energy Research Scientific Computing Center (NERSC) to create mesmerizing computer-generated visualization showing the slow and sedate disappearance of wobbly foams one burst bubble at a time. The applied mathematicians, James A. Sethian and Robert I. Saye, will report their results in the May 10 issue of Science . Sethian leads the Mathematics Group at Berkeley Lab and is a professor of Mathematics at UC Berkeley. Last month, Sethian was elected to the National Academy of Sciences.