The radial response of a bubble in a liquid subject to an acoustic field has long been the object of considerable interest [see, for example, W. Lauterborn, J. Acoust. Soc. Am.59, 283–293 (1976); B. E. Noltingk and E. A. Neppiras, Proc. Phys. Soc. London Ser. B63, 674 (1950)]. However, the most often generated graph in these theoretical and numerical studies, the radius‐time (R‐T) curve, has never been experimentally observed until now. The first direct observation of the R‐T response of a single bubble will be presented. The measurements were made on a bubble “levitated” [M. Strasberg, J. Acoust. Soc. Am.33, 359 (1961)] near the antinode of an acoustic stationary wave by digitizing the output of a photodiode monitoring the intensity of laser light scattered by the bubble. Comparisons will be made with the results of some recent numerical models. [Research supported by ONR.]