Introduction Laboratory study of atmospheric phenomena provides a controlled, steady environment which is usually difficult to obtain in the turbulent atmosphere. These ideas are foundation-stones of our understanding of atmospheric clouds. Such ideas came from careful laboratory studies of the behavior of particles under well controlled conditions. There are different approaches to improve our understanding of things which go on in the atmosphere, and there are different ways of deciding when problems exist and when they do not.
Insights come by showing that some things are unimportant as well as showing that some are.
Laboratory cloud physics and cloud chemistry are perhaps unique in atmospheric science in that direct, controlled experiments are possible. If we can specify a system well enough, it may be recreated in the laboratory, as a controlled experiment. It may provide an experimental challenge to do so, but that is where the experimentalist's skill becomes paramount. Results are to be set within a physical or numerical model, to provide appropriate curve-fits and boundary conditions for a larger scale context. As an example, the growth of a snow crystal may be simulated in a system reproducing temperature, supersaturation, fall velocity, and air pressure.