Dec. 7, 2000 A physics professor in California has come up with answers to all of your questions about snow. Caltech's Ken Libbrecht explains everything from why no two snowflakes are identical, to where snowflakes appear in popular culture.
When Libbrecht first got interested in snow crystals in 1996, he found information hard to find. "The information was scattered all over, mostly in decades-old books and journals," he says. After deciding that others might be just as curious about the white stuff as he was, Libbrecht created his website "Snow Crystals" (http://snowcrystals.net). "The web is the perfect medium for this," says Libbrecht, "especially since the snow crystal story naturally includes lots of pictures."
In addition to marvelous pictures, Libbrecht explains the basics of how snowflakes form. A typical snow crystal begins in a cloud as a very simple hexagonal ice crystal that forms around a small dust particle. As it gets bigger, the crystal sprouts six tiny arms. The snowflake continues to grow and develop, depending on the kinds of temperatures it experiences in the cloud. At one temperature the crystal's arms could gain a flat sectored plate, then later, at another temperature, develop long, thin, "dendritic" extensions. "By looking at a snow crystal on the ground," says Libbrecht, "one can say something about its history – what conditions it encountered during its brief existence."
The professor says the response to his site has been great. He receives e-mail from people who use it for all kinds of research. "One of my favorite e-mails," Libbrecht recounts, "was from a woman who was going to get some snowflake tattoos, and used the pictures on the site for design ideas, and to make sure her designs were realistic."
Libbrecht also answers the age old question about whether there are really no two identical snowflakes. "They're like faces," he says, " When snow crystals are born, and are very small and simple, they look alike. As they grow, they all follow slightly different paths, and so they each grow differently. With time, each grows into its own complex and unique shape." And while two simple snowflakes may look alike, the website explains, the chance of two crystals being identical in the lifetime of the universe is essentially zero.
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The above story is reprinted from materials provided by American Institute of Physics -- Inside Science News Service.
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