[ot][spam][crazy] Making Free Electricity out of a Water Bomb

[k]

When water freezes to ice, it exerts pressure and expands.

This is a physical force that could be harnessed for power.  The power
available is probably a function of the temperature change available,
the mass of material holding that temperature, and the amount of water
available.

If the temperature change does not cross the freezing point of water,
a substance other than water could be chosen, in theory.

Note: the planet is covered in water, and during winter something like
a quarter of the planet's surface crosses below freezing.  So there's
potentially a lot of power available from this.