A simplified model of the interaction between Buckminsterfullerene C60 and a water surface is derived. Using this model, we construct a Langevin equation of motion for each fullerene molecule. The rates of various processes occurring in Langmuir films can then be estimated. We consider the rate of escape of molecules from the surface, the rate at which molecules in a monolayer film are promoted to a second layer, and the rate of hopping diffusion in the second layer. These results are used to interpret the published results of experiments with Langmuir films of C60 and to suggest further experiments.