The Secret To Preserving Snowflakes

You might wonder how someone studies snowflakes under a microscope. Once a snowflake lands on a glass slide, wouldn't it melt by the time you got it under the lens?

Atmospheric scientists use a special technique that makes a very accurate copy of snowflakes.

They take a slide and spray it with a special chemical solution called Formvar, Pao Wang, atmospheric scientist, explains. You leave it on the slide and then put the slide outside when it snows.

When the snowflakes hit the slide, the Formvar immediately crawls on the surface of the flakes. By the time the flakes melt or evaporate, the Formvar has already hardened and made a kind of plastic shell in the same shape as the snowflake. This is called a Formvar replica. ''Think of it as a very tight 'wrapping' of a snowflake,'' Dr. Wang explains.

Scientists can then keep the snowflake replicas on file and look at them under a microscope at any time.