A very slightly different method was used by Kelvin in the 1880s to derive the same expressions. Surface tension below is given by σ and the nkT approach is used instead of RT where n is the number or number density of particles in the system.



The above graph shows important conditions of droplet growth. For instance, for a droplet radius of .01 μm to grow it would require a relative humidity of 112% (super saturation of 12%) and this just doesn't happen in the real world. A droplet of radius 1 μm requires only .12% of super saturation which does happen.