  We present experiments investigating the growth of ice crystals from water
vapor in air using a free-fall convection chamber. We measured growth rates at
temperatures of -5 C and -10 C as a function of supersaturation at an air
pressure near one bar. We compared our data with numerical models of
diffusion-limited growth based on cellular automata to extract surface growth
parameters at different temperatures and supersaturations. From these
investigations we hope to better understand the surface molecular dynamics that
determine crystal growth rates and morphologies.
