Ice, Ice, Baby

I was chatting with a friend about ice.

In short, we talked about how interesting it is that pressure, even without heat, can melt ice.

I remember an experiment where you loop a string around a block of ice, then put a weight on the bottom part of the loop, so that the string is heavy on the ice (in other words, there’s pressure wherever it touches the ice). Then put it all back in the freezer.

Even though it stays cold, the pressure of the string will melt the part of the ice it’s touching, so that the string moves down through the block, eventually coming out the other end. Slowly.

Now I also remember a different friend, who’d said that this property of ice is what allows ice skates to work. If you think about it, ice is a solid, and it shouldn’t be that easy to push a metal strip across it. Imagine trying to skate across any other solid.

But it’s not that simple. As I looked around on the Web, I found this article, which explains that the pressure of the skate on the ice isn’t enough to account for the slipperiness. And they’re not sure what does account for it!

So that’s cool.

And while looking for a video of the experiment I remember, I saw the one below. It’s completely unrelated to water ice, but it looks very fun to try.

One Response to Ice, Ice, Baby

  1. Margo January 30, 2010 at 8:35 pm #

    This is so cool, I could watch it again and again. Interesting about the ice and string thing too. Might have to try that one with the boys. Unfortunately, kids are almost used to amzing things happening all the time (b/c everything is amazing if you haven’t seen it yet, and they haven’t seen anything!), so it may not have the same wowness. Then again, it may b/c it’s still very cool.

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