Growth of Breath Figures

Measurements are reported of the growth of breath figures, the patterns that form when a vapor is condensed onto a cold surface. The pattern for water on glass was studied by direct observation and light scattering as a function of the contact angle θ, flux F, degree of supersaturation ΔT, and time t. When θ=0^∘, a uniform layer forms whose thickness grows as t at constant F and ΔT. For θ=90^∘ droplets are formed; at constant F and ΔT the radius of an isolated droplet grows as t0.23, but as a result of coalescences the average droplet radius grows as t0.75. The growth process is self-similar---coalescences simply rescale the distances and leave the basic droplet pattern unaltered.