The mechanics of transportation of sand under the influence of wave action was studied using artificially induced radioactivity. A sample of naturally occurring quartz sand is taken from the area of study, subjected to slow neutron irradiation, and then reintroduced into the area. The movement of the quartz is traced by sampling the sediment on the bottom and assaying for phosphorus‐32, which is the principal radio isotope formed from the slow neutron irradiation of natural quartz sands.In a field experiment, 860 g of irradiated quartz sand was reintroduced as a point source on the sea floor off Scripps Beach. The experiment showed that the dispersal of sand by wave action was more rapid than expected, and that the movement of this small amount of sand could be followed for about 7 to 24 hr. The irradiated sand was released on the bottom by divers and samples were obtained on a grid at the time intervals of ¼, 1, 3½, 7½, and 24 hr, and several days later. At the point of introduction the water was 10 ft deep and the surface waves were about 1¼ ft high. The waves caused the sand to spread in an elliptical pattern with an elongate onshore‐offshore axis. The sampling indicated that the 860 g of irradiated fine sand had been dispersed over an area of approximately three‐quarters of a square mile in 24 hr. The sensitivity of detection for this experiment was approximately 1 grain of sand i