Investigation of the homogeneous nucleation of water vapor using a diffusion cloud chamber

The temperature variation of the critical supersaturation for water vapor has been measured using a diffusion cloud chamber. By attaching a layer of glass wool to the upper plate of the chamber, the persistent refusal (in previous experiments) of water to wet this plate has been overcome. As a result, for the first time measurements without appreciable scatter have been achieved for water vapor. The resulting temperature dependence agrees reasonably well with that predicted by the classical Becker-Doering-Zeldovitch theory, while the experimental curve is shifted by approximately 8% from the classical prediction.