Very likely if we define alike to mean that we would have trouble distinguishing them under a microscope and if we include the crystals that hardly develop beyond the prism stage—that is, the smallest snow crystals," Nelson said. IE 11 is not supported. For an optimal experience visit our site on another browser. Politics Covid U. News World Opinion Business. Share this —. Follow NBC News. By By Charles Q. A snowflake begins to form when water vapor condenses around a speck of dust high in the clouds—up to six miles ten kilometers up—and then crystallizes.
How the water vapor keeps on condensing and where the snowflake falls "is what determines the way the snowflake, or snow crystal, looks when it lands on your coat sleeve," Gosnell said. Below that, needles form. A few degrees colder yields hollow columns; chillier yet, fernlike stars. These crystals—usually six-sided because of the way hydrogen atoms bond with oxygen to create water—may eventually sprout branches, which continue to grow as additional water molecules cluster on the crystals' surfaces.
See a snowflake photo gallery. Humidity also plays a role. Drier air encourages growth across flat surfaces, for example, while higher humidity encourages growth at the tips, edges, and corners.
More water vapor also leads to faster-growing and more intricate crystals. To further complicate matters, as a crystal falls, frost could freeze to it or another passing flake could break off some of the crystal's branches.
Even the the approach of a water drop can influence how a branch grows. Jon Nelson is a research scientist at Ritsumeikan University in Kyoto, Japan, who studies snowflakes. For example, scientists are uncertain why crystals take different shapes at different temperatures and do not know precisely how temperature and humidity affect growth. In the daytime, for example, thick clouds full of snow crystals are believed to reflect sunlight, keeping Earth cool.
At night, however, the same clouds act as a blanket, absorbing the heat given off by Earth. Researchers do know enough to confirm that the "no two snowflakes are alike" adage is likely true for fully developed snowflakes, Nelson added. But it may not hold for some flakes that fall out in the early stages of crystal formation, he said.
His parents purchased a microscope for him so he could examine these minuscule wonders of nature. Snowflakes were examined using this microscope. Not only did he examine the snowflakes under his microscope, he contrived a microscope-bellows camera combination in order to take photographs snowflakes — outdoors of course!
Wilson Bentley prepares to photograph a snowflake using his microscope-bellows camera. Over his life time he took well over microphotographs of snowflakes and thus discovered that no two snowflakes were alike. Today he is best known for his scientific research and photographic work in the study of snowflakes. This is why snowflake growth is often symmetrical. On the other hand, every snowflake is buffeted by changing winds, sunlight and other variables, notes Mary Jane Shultz, a chemist at Tufts University who published a recent essay on snowflake physics.
As each crystal submits to the chaos of a cloud, they all take on slightly different forms, she explains. The earliest recorded musings on these delicate shapes date to B. But the first scientist to try to understand why this happens was probably Johannes Kepler, the German scientist and polymath. He would have recalled a letter from his contemporary Thomas Harriot, an English scientist and astronomer who, among many roles, served as a navigator for the explorer Sir Walter Raleigh.
Hexagonal patterns seemed the best way to pack spheres closely together, Harriot found, and he corresponded about it with Kepler. Indeed, molecules of water, with their two hydrogens and one oxygen, tend to lock together to form hexagonal arrays.
Kepler and his contemporaries could not have known how much this matters. Aside from helping grow snowflakes, this hexagonal structure makes ice less dense than liquid water, which hugely affects geochemistry, geophysics and climate. In the s, an American photographer named Wilson Bentley — from the cold, quality-snow-producing village of Jericho, Vermont — began making the first snow crystal images using photographic plates.
He produced more than 5, images before eventually succumbing to pneumonia. Then, in the s, the Japanese researcher Ukichiro Nakaya began a systematic study of the different snow crystal types. By midcentury, Nakaya was producing snowflakes in a lab, using individual rabbit hairs to suspend frost crystals in refrigerated air where they could grow into full-fledged snowflakes.
He tinkered with humidity and temperature settings to grow the two main crystal types and assembled his seminal catalog of possible shapes.
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