Saturday, January 12, 2008

While no winter weather for much of NC, we talked about snow in Cary!

Today we have a pleasant day across much of North Carolina. The cold front that passed through our state Friday (while not bringing about much of any rain) is located just off our coast and will stay that way for the weekend.

Along this front we'll see a wave of low pressure develop to the south and it is expected to move northward along this front on Sunday bringing us the possibility of some clouds and sprinkles.

I got to talk about winter weather and snowflakes to the Kids Korner group today at West Regional library in Cary . (Thanks to Sue Mellott for inviting News 14, we'll post pics if they become available.) This library is about 1 year old and its a great walkable / bikeable destination for a good book.

We discussed the different snowflakes that are possible and what kinds of temperatures are necessary for them. The book we used was Ken Libbrecht's Field Guide to Snowflakes ( in case its on your shelf as well!) . We even had folks from Vermont who shared about snow in their area this year (they're on their way to warmer locations...thats a clue as to how they needed to get away from it)!

What makes snow white?
Snow is a whole bunch of individual ice crystals arranged together. When light enters a layer of snow, it goes through an ice crystal on the top, which changes its direction slightly and sends it on to a new ice crystal, which does the same thing. Eventually the light bounces right back out of the pile! The "color" of all the frequencies in the visible spectrum combined in equal measure is white, so this is the color we see in snow, while it is not the color we see in the individual ice crystals that form snow.

How is snow made for ski slopes, etc.?
It is produced by a machine that uses a high-pressure pump to spray a mist of water into cold air. The water droplets subsequently crystallize to form fake snow.
In a snow machine, water is first mixed with a nucleating material. It is then pressurized and forced through an atomizing nozzle. This turns the water into a mist, which is then injected with compressed air to make it a fine mist. As it exits the snow machine, the mist crystallizes on the nucleator and turns into tiny snow-like ice particles. Depending on the quality of the snow machine, the artificial snow can be as good as natural snow.

Our vermont couple brought up a very noteworthy name in snow research:

(courtesy website:

You've heard the phrase "no two snowflakes are like"...this man was the one to prove it!
The discovery was made in the small rural town of Jericho, Vermont by Wilson A. Bentley (1865-1931).
He was a self-educated farmer who adapted a camera to a microscope and after years of trial and error, he became the first person to photograph a single snow crystal in 1885.

He ended up photographing over 5000 snowflakes and not one looked like another! Because of his work he went down in history affectionately as "Snowflake" Bentley.

Have a great weekend!

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