http://www.azcentral.com/arizonarepublic/news/articles/0223clay0223.html

What's cool on ice cubes are the spikes

Feb. 23, 2006 12:00 AM

I am feeling perky today. As a rule, perkiness is not one of my leading qualities. However, I just got my taxes done, and for the first time in a long time, I didn't get gooned. Or at least I didn't get gooned as much as I usually do.

So perk up and let us consider today's theme, which is about stuff that is really cold. Colder even than my masters' flinty hearts.

First, for you weather wonks. I just finished the paperback edition of The Children's Blizzard by David Laskin. It's a really chilling, no pun intended, account of a humongous blizzard that hit the Dakotas and much of the rest of the Upper Midwest in January 1888.

If you are interested in the early days of weather forecasting or life on the prairies back then or just exactly what happens to you when you freeze to death, you should check it out.

Next, there was a really interesting article in Tuesday's New York Times about just exactly why ice is slippery and why these Olympic skater babes can just glide along all over it. Unless they fall down. I suppose I could just have waited a year or so and stolen all this info and pretended I knew it myself, but I thought that what with the Winter Olympics being on television 32 hours a day, you might be interested. You can find it at www.nytimes.com /science.

Last, here's a question that, for some reason, has come in twice in the past few days. I paraphrase:

Why is it that sometimes ice cubes from the freezer have little spikes of ice sticking up from them?

OK, the thing to remember here is that unlike most things, water expands rather than contracts when it freezes.

Now, a couple of years ago some physicists at Caltech actually did a study of this spike thing and made thousands of ice cubes and filmed them as they froze and took notes and that sort of stuff.

This is what they figured out: It's the Bally-Dorsey effect. Don't ask me who Bally and Dorsey are or were. I don't know.

Anyway, the water freezes on the surface first along the edges of the cube. As it freezes, it expands so the surface is stretched and sometimes a little hole is left. As the cubes continue to freeze, water will be pushed up through that hole to form a little tube and more water is pushed into the tube, leaving a little spike on the cube.

It's looks kind of like a stalactite. Or stalagmite. I can never remember which is which.

Reach Thompson at clay .thompson@arizonarepublic .com or (602) 444-8612.