> 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?
MMB
-- (NOTE: Robotlike replies to the above address will fail; *noncommercial* communications are welcome; kindly substitute a hyphen for the asterisk in the above address. Sorry for any inconvenience.)