VOA标准英语2009年-Website of the Week — SnowCrystals.c（在线收听）

An online guide to snow and other ice phenomena

Art Chimes | Washington, DC 18 December 2009

 
Photo: SnowCrystals.com
Time again for our Website of the Week, when we showcase interesting and innovative online destinations.

For those of us in the northern hemisphere, Monday is the first day of Winter, which seems a good time to check out a website that's all about the snow.

"SnowCrystals.com is a website that is about snowflakes and snow crystals and generally ice phenomena," explains Kenneth Libbrecht,a physics professor at the California Institute of Technology (Caltech), and for a decade he's been posting gorgeous photographs of snowflakes and a lot more on his website, SnowCrystals.com.

He says the site is a "little guide to different types of snowflakes – sectored plates and capped columns and hollow columns and all different types of crystals. I talk about some of the history of snow flakes and people who have photographed them and studied them before. I talk some about the physics of snowflakes. And I even have a section on what I call 'designer snowflakes,' which is us growing crystals in the lab, trying to understand how the physics works."

It's often said that no two snowflakes are alike. But is that literally true? Kenneth Libbrecht says it depends on what kind you're talking about, but if you mean the classic, complex six-sided version, the answer is yes.

"They are so complicated that if you tried to estimate how many ways you can make a snowflake, you get a huge number – not just billions or trillions, but bigger than the number of atoms in the universe. So the odds of seeing any two exactly alike are essentially zero."

Lots more – including videos of designer snowflakes being grown in the lab – at SnowCrystals.com, or get the link from our site, VOAnews.com.