Weekend America

Change of Seasons

Seeing Snowflakes

Suzie Lechtenberg

JANUARY 19, 2008

Stellar Dendrite

(Kenneth Libbrecht)

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Ken Libbrecht: Yeah, I'm kind of the snowflake guy, the snowflake expert, you might say.

My name is Ken Libbrecht. I'm a professor of physics at Caltech and I study the physics of how ice crystals grow. And I like to photograph snowflakes!

They are somewhat ephemeral. First of all, you have to wait for it to snow. Then I have a piece of cardboard and I let the crystals fall on the cardboard. You can't look at them on the ground because they sort of undergo changes. And after a very short time, they don't look very nice when they're on the ground. They have to be falling out of the sky.

I take a close look and try to find nice looking ones, photogenic snowflakes, if you will. Then I pick up an individual snowflake with a little paintbrush and drop it onto a microscope slide. I have a specially-made microscope for photographing snowflakes. Then I just snap the picture.

Yes, you do break a lot. But they're falling out of the sky so you just go and get another one.

Snowflakes come in a lot of different varieties. People don't usually think about it. We're all used to the kind of snowflakes you see on advertisements around Christmas time in the middle of the winter: the stellar crystals with branching and six-fold symmetry. Those are common, but there are lots of other types too. Like capped columns, where the columns have two plates growing on either end. Arrowhead-type crystals, which look a little like arrowheads. There are simple stars and fernlike stellar dendrites, which have lots of branching and side branching. It's surprising how much variety of different crystal types you can find!

When I'm photographing, I like to look for beautiful, stellar crystals because they can be very elaborate, very lacy, and really a lot of fun to look at. That's because they're interesting and they're unusual. One of the things I like to do, because I'm involved with understanding the physics of this, is to try to understand how they form. So when I see a funny-looking snow crystal, I can try to puzzle over where it came from and how it got that shape. So I do some of that too.

Every place is good. Well, Miami is very bad and Los Angeles is bad. I like places that are very cold because the best crystals form when it's five or 10 degrees Fahrenheit. So that's pretty cold. I've been up in Alaska. And Vermont is good. Northern Michigan, where it snows about an inch a day, sometimes produces very nice crystals as well.

I camp out and wait for it to snow. Sometimes, I'll wait around until two in the morning to get really nice looking snowflakes to photograph. So I never really exactly know what I'm going to find when I go out looking.

I find that it's really fun. To me, it's the most fun you can have out in the snow, when it's snowing anyway. I just want to say, since this is a weekend show, and you're telling people about what people do and what they might want to think about doing, I'm always encouraging people to get a little magnifying glass the next time it snows and go outside and have a look at what's falling out of the sky. You really might be surprised by how interesting it is!

• Music Bridge:

  A Miniature Finale

  Artist: Lullatone

  CD: Little Songs About Raindrops (Audio Dregs Records)

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