ИСТИНА

The crystal habit diagrams are probably the most known result of the natural snow crystals studies. The dependence of snow crystals' shape on temperature and supersaturation, their modifications due to various side effects and incorporation of additional dimensions are already part of common knowledge. However, practical application of this knowledge, for example growth of snow crystals of required shape, still is mainly the subject of theoretical and numerical exercises. A device was constructed in attempt to produce continuously machine-made snow form crystals of natural shapes. The procedure involves formation and maintaining an artificial cloud in closed chamber under sub-zero temperature, initiation of ice nucleus formation and growth of snow crystals from these nucleus by regulating the temperature and mass supply to the growing crystals. The data on the resulting amount and shape of the snow crystals falling from such cloud were collected and analyzed. The results suggest that even in the small volume of the regulated device, the phase transitions construct highly variable temperature field not easily equilibrating with the surrounding environment. Mixed shapes of crystals were found in all the experimental runs, and though the major types of formed crystals shapes can be related to temperature similarly to the published crystal habit diagrams, some crystal shapes could be found at practically any mean temperature of the experimental volume.