A cloud chamber system was developed to study the evaporation of water and a series of experiments performed to demonstrate its ability to carry out such investigations. An analytic method was developed to interpret the results of the study and a relationship between evaporation resistance and water surface tension established. The effect on evaporation of long-chain alcohol monolayers was examined and Tetra, Hexa, and Octadecanol alcohols found to be better inhibitors than Dodecanol. Two particularly important applications of the cloud chamber system developed: the study of the effect of dissolved contaminants on evaporation resistance of water and the effect of surface barriers on the evaporation rate. NaCl inhibits evaporation strongly with the resistance to evaporation increasing with the concentration of salt in solution. CaCl apparently reduced the resistance to evaporation. The development of a cloud within the chamber as a function of chamber atmosphere temperature gradient showed a fog-like behavior for gradients greater than 1øC/cm. For smaller gradients the cloud development was generally uniform throughout the chamber. Cloud development as a function of water temperature was observed and a variation in evaporation resistance noted.

Project No. A-024-3109-35