From The flake's progress at csmonitor.com.
Posted on December 30, 2002 09:17 PM. Filed under: environment.For Cal Tech physicist Kenneth Libbrecht, the birth and evolution of an ice crystal carries more than enough mystery to keep a lab busy.
The anatomy of ice surfaces and how they influence the growth of ice crystals are "all pretty basic stuff," he notes. "But we are surprisingly ignorant of even these fundamental issues."
His lab has been focusing on growing ice crystals under tightly controlled conditions, then measuring how an ice crystal's size and shape change with time. One intriguing result indicates that while a crystal's growth rate depends on temperature and the extent of supersaturation, other gases in the air may also affect its growth.
Experiments using a vacuum chamber filled with nothing but water vapor yielded crystals that were little more than simple prisms, while in air, the crystals grew in a variety of plate-like and needle-like shapes.
All this is of interest to atmospheric chemists looking to track the life cycle of pollutants and their constituent gases in the atmosphere. [continue]