Re: earth/moon relationship

Michael M. Butler (mbutler@comp*
Mon, 27 Oct 1997 00:12:21 -0800 wrote:

> Things expand when they cool.

Hmm, that's an assertion anyone can test. I just checked. Thermal expansion
coefficients are published in big books, and most of the ones I looked at are
positive, not negative. SO I feel confident saying:

Actually, most solids, liquids and gases don't.

Water does, when it makes ice. Steam doesn't, when it makes water. Both these
facts are part of what makes Earth such a nice place. Ice melts, rather than
sinks, to name one good thing.

Most things get smaller when they cool. Example: lava cracks as it solidifies.
Why? It is contracting, and it can only contract so far before cracks appear.
Another example: which would you use to loosen a pipe fitting, heat or cold?


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