Building a Better Snowflake by Margaret Wertheim and Kenneth Libbrecht

In physics, research, science on August 19, 2014 at 02:49

From: Building a Better Snowflake: An Interview with Margaret Wertheim and Kenneth Libbrecht, Cabinet,

You are also following in the footsteps of the Japanese physicist Ukichiro Nakaya, who pioneered the classification of snowflakes. Tell us a bit about his work.

Nakaya was a student in the 1920s trained in nuclear physics. Like many physicists, he had trouble finding a job because there are only so many positions for nuclear physicists. He couldn’t get a job in Tokyo and ended up at the University of Hokkaido in the snowy north. There were no nuclear facilities there, so he had to find something else to do. In Hokkaido they get wonderful snow, so he decided this was an opportunity and started studying snowflakes. He was the first serious scientist to do this. He went outside and categorized things, but more importantly he started growing them in the lab under controlled conditions. Nakaya found out they grow differently at different temperatures—which is still a fundamental problem. We don’t understand why that is. He wrote a wonderful book called Snow Crystals about how you do science starting from nothing.

He tried to grow snow crystals on different kinds of threads. What did he use?

hexagonal_plate_FINALHe wanted to understand snow crystals as they fall out of the sky—which is basically single ice crystals. But when he tried growing them in the lab, mostly he got frost, which is a whole collection of crystals interfering with each other. This makes it hard to see what’s going on. It’s not easy to grow single crystals—you need something for them to grow on. In the sky, they grow on dust particles. Nakaya tried all sorts of things: silk, spiders webs, fine wires. Finally, he found that rabbit hair worked well. He decided it was because the hair is covered in a thin film of residual oil. It has these knobby things on it every now and then, and the knobby things are where the crystals start to grow. He was able to grow individual crystals provided he dried out the rabbit hair beforehand in a desiccator. We’re doing similar things, but we’ve got a different technique. I never liked the rabbit hair.

Read the interview

Reposted with permission from: Cabinet


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