Re: pinhole ice stalagmites

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From: pauld@exploratorium.edu
Date: Thu Aug 26 1999 - 02:59:56 PDT 

Message-Id: <199908261659.JAA09850@isaac.exploratorium.edu>
From: pauld@exploratorium.edu
Subject: Re: pinhole ice stalagmites
Date: Thu, 26 Aug 99 09:59:56 +0000

Hi Eric

There were some photos and discussion of this pnemomenon in the Physics Teacher
magazine last year.

The best guess was that the outside of the ice cube froze imprisoning water
inside the cube.
The water expanded as it froze inside its ice prison putting the trapped water
inside under high pressure.
Whenever this high pressure cracked the top of the ice just right, the high
pressure water could leak out forming a spire of ice.

I've seen these in my freezer too, next time I'll have to photograph them.

Hey, here's a cool activity from Tom Tit.
put a drop or three of food color into a sugar cube.
make a thin layer of milk in a dish, perhaps 1/2 cm deep.
Put the sugar cube into the center of the dish...Wow!

They are all waiting for your book to be published.

Paul Doherty

> A friend asked me a question I couldn't answer:
>
> She says that often, when she leaves ice cubes in her freezer for long
> periods of time, they develop stalagmite formations (cave like columns).
> She asked me how/why they form. I said I would get back to her on
> thisS..any guesses?
>
> Eric Muller
> Exploratorium Teacher Institute
> Science Teacher on Staff
> 3601 Lyon St.
> San Francisco, CA 94123
>
> 415-387-7930
> emuller@exploratorium.edu
>
> www.doscience.com
>
>
>
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