Cold Crystal Growth
How is it that crystals grow in cold temperatures?
This is not "always" true, but usually is. Here is why. Most substances -- I am
thinking here about substances dissolved in a solvent, usually water, are less
soluble than at higher temperatures. So as the temperature is carefully and slowly
decreased, the substance becomes less soluble and it forms a crystal (or crystals).
A few substances have reverse solubility in water. Those substances grow crystals
by carefully and slowly increasing the temperature. There is another less common
method of growing crystals, and that is by precipitating the crystal from the liquid
phase of the substance with no solvent. In this case, crystals ALWAYS form by cooling
the liquid, not heating it. The "reason" for this is that it always takes heat to melt
a crystal. This fact guarantees that cooling the liquid produces crystals, not heating
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Update: June 2012