Tuesday, November 27, 2007  Curvature, Clouds and Capillarity
One of the fundamental results from the Laplace-Young derivation
is that the pressure on the concave side of a curved liquid-
vapor surface is greater than that on the convex side. Lord
Kelvin immediately saw the impact a curved surface would have on
the equilibrium vapor pressure (when comparted to a flat
surface).  For example, consider a spherical droplet, which puts
the liquid on the concave side of the interface (which is at
higher pressure than the convex side). Essentially being an
applied pressure, this will in turn increase the vapor pressure
above the surface (see previous lecture on how external pressure
increases the escape tendency of the liquid, leading to the
Kelvin equation:  ln(Pdrop/Pbulk) = 2γM/rρRT  One example of its
meteorophysicochemical consequences: Moist air rises naturally
from the surface of the earth and will experience at some
altitude a combination of pressure and temperature that makes
condensation favorable (in term