I have a vague recollection of the explanation of why water expands as it freezes…something about the electrical charge of the water molecules “wanting” to align themselves in a certain way as they crystallize, and water is fluid enough for them to do so. My question is, why is it just water expands as it solidifies, or are there other susbstances that do that too?
I believe strontium does as well.
Methinks you should ask Tommy Lee 
Explanation:expands as it solidifies!Get it?
Water is the only thing I’ve heard of. I couldn’t find anything on strontium. Here’s an explanation.
Beatle—
Thanks! That was it, the hydrogen bond vs the covalent bond. 'Preciate it.
I’m curious about that strontium thing, but I’ll research that on my own.
I don’t recall hearing of strontium having that property, but it might. I do have vague recollections of bismuth being that way… though it may only be alloys of bismuth that do.
Type metal definitely does; I think it’s one of those bismuth alloys.
At any rate, it’s a very rare property.
If I recall my physics class correctly, plutonium has the rather strange property of expanding and contracting during its different phases, some of which include contractingwhen heated.
Gallium is an element that in it’s pure state is a metal that freezes/melts at about 30 degrees Celsius (86 Fahrenheit). It too expands when it solidifies.
A classic gag is to make a spoon out of gallium and give it to someone to stir their coffee with.