The volume of gaseous oxygen produced during the Briggs-Rauscher (BR) oscillating reaction with acetone was measured. The rates of oscillatory oxygen evolution were calculated and the effects of stirring rate and addition of acrylamide on the oscillations were studied. The dynamic behavior of the modified BR reaction was modeled by mechanisms suggested by Noyes and Furrow (J. Am Chem. Soc. 1982, 104, 45) and De Kepper and Epstein (J. Am. Chem. Soc. 1982, 104, 49), supplemented by the physical processes of the iodine and oxygen interphase transport. The calculated oscillatory parameters are in satisfactory agreement with experiment.