When drilling a hole into a rock, filling it with water, and freezing it, why does it expand outward to break the rock rather than extrude out of the hole that was drilled?
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Water is a really weird thing, as far as physics is concerned. It’s a polar molecule — the oxygen atom “holds onto” electrons more tightly than the hydrogens do. This gives rise to “hydrogen bonds” between the hydrogen of one water molecule and the oxygen of another.
The strength of this bond is usually defeated by the thermal energy of the water — the energy the individual molecules have as they move about in the liquid state. So, normally, water doesn’t get the chance to establish them very much.
As you start taking thermal energy out of the water, though, these hydrogen bonds can assert themselves and begin to lock the water into ice. Past four degrees celsius, the hydrogen bonds become stronger, and so ice expands as it freezes.
Saliently, it does this in all directions, because what’s stopping it?
Water expands when it freezes. So if water get into cracks of a rock and then it freezes it could break the rock. Same thing as frozen water in a glass jar
This can happen, to some extent. Ever pulled out a tray of ice cubes from your freezer and [found them to be spiky](https://i.ytimg.com/vi/5RLQ9WMP2Es/maxresdefault.jpg)? Or perhaps, more commonly, with a little raised dimple in the center? That’s more or less caused by exactly what you describe.
However, that’s only really possible when the ice freezes top-down due to the cold air in your freezer, with the ice cube tray having nice, smooth, sloped or curved edges that help the ice cube push up and out as it grows.
Water poured into rough, craggy, freezing cold crevices, on the other hand, freeze from all sides inward simultaneously, locking the water’s shape and not allowing it to “squeeze out”. So it simply expands. You can block the expansion if you have a container that’s capable of containing the pressure. Solid rock is not one of those containers.
Usually, the rock cools down from the surface to core. So the top of the water freezes first, essentially trapping the liquid under it so it cannot squirt out when freezing and expanding. Water has this property where it’s density is highest at 4deg C. So the bottom of the water is always last to freeze. Also see ice-fishing
it freezes where it contacts the ground first. So all the sides, and even the top freeze first. The inner portion is insulated a bit, and stays liquid till near the end.
It’s when that inner core freezes and has nowhere to go that the damage occurs. It’ll push out, and up. and not in a uniform press either. This is what causes it to break.
They do a little bit. Ice will expand upward a little bit, but it’s not fluid enough that *all* of it will move upward seeking the path of least resistance. The ice at the bottom of the hole is just going to expand immediately outward where it is, into the sides of the rock.
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