This always confuses me, is it cold that expands and heat contracts?
or the other way around, cold contracts & heat expands?
or as steam & ice spikes suggest, both steam & ice spikes expand? (free energy?)
In: Chemistry
The reason ice crystals expand has been explained handily by others here (i.e. the ordered crystal structure of ice is actually less dense than the randomly-jumbled orientation of liquid water molecules).
The reason steam creates pressure is that steam is a gas, and gases always expand to fill the available space. If the gas is within a flexible container, like a balloon, the gas will push outwards on the sides of the container and make it expand. If the gas is inside a rigid container, like a metal boiler, it will still push against the outside of the container, which will not expand, but will cause the gas to push back against itself. This is essentially what pressure is – gas molecules pushing against everything.
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