The Mistery of Snowflakes

Did you know that snowflake's shape can change itself in different temperature?

That no two snowflakes look exactly alike is fairly common knowledge. Less well known is that snowflake's shape depends on temperature at which it forms. When the mercury hovers between -1 degree centigrade and -3 degrees centigrade, snowflakes crystallize as plates and dendrites.

At about -5 degrees centigrade, needles and hollow columns appear. At still colder temperatures, the flakes design returns to dendrites and plates. And when snowflakes start forming into columns at around -5 degrees centigrade but then encounter cooler or warmer temperatures, the crystals end up as capped columns (part column, part plate).

What no one knows is why temperature affects crystal formation. Kenneth Libbrecht, chair of the physics department at the California Institute of Technology, is trying to solve the mystery by studying thousands of flakes, both in wild, such us Ontario, Michigan, and Alaska, and his lab, where he grows snowflakes under controlled conditions. By comparing snowflake development with theories of crystal growth, he may unlock the secret of how flakes take shape.

According to Libbrecht, the shifting of snowflake may even hold clues to some bigger question of global warming. "Nature is one unstable system haeped on another another," he says. "Knowing where the tipping points are is key to learning if global climate is similar thresholds where sudden changes may occur."