# Ice Force

How many pounds of pressure are exerted by a gallon of freezing water?

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How much would you like it to be? Pressure along the liquid-solid coexistence line is independent of volume; it depends only upon the temperature at which you establish the liquid-solid equilibrium. The liquid-solid coexistence begins at the triple point of water, 273.16 K and x Pa, proceeds to lower temperatures and higher pressures, 273.15 K and 0.1 MPa (ordinary freezing pt.), and goes wandering off through a fascinating phase diagram. At near normal conditions, you can figure something like 10 MPa/K for water in confined vessels --- once you cool to a point at which the pressure equals the burst or deformation limit for the vessel, the water freezes and the vessel bursts or deforms to accommodate the larger volume of the solid.

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Originally posted by Bystander
How much would you like it to be? Pressure along the liquid-solid coexistence line is independent of volume; it depends only upon the temperature at which you establish the liquid-solid equilibrium. The liquid-solid coexistence begins at the triple point of water, 273.16 K and x Pa, proceeds to lower temperatures and higher pressures, 273.15 K and 0.1 MPa (ordinary freezing pt.), and goes wandering off through a fascinating phase diagram. At near normal conditions, you can figure something like 10 MPa/K for water in confined vessels --- once you cool to a point at which the pressure equals the burst or deformation limit for the vessel, the water freezes and the vessel bursts or deforms to accommodate the larger volume of the solid.

nice fact
just checking:
10 MPa/K is about 1000 tons per square meter per degree of temperature.
So I imagine I have a cylinder of cold water,
the bore of the cylinder is 1 square meter,
a 1000 ton weight rests on a piston in this cylinder
(so the pressure exerted on the water is about 10 MPa
above ambient)

If I wish to lift the weight by freezing the water in the cylinder
then according to your formula it will not freeze at 0 celsius
but has to be cooled to -1 celsius.

If I load the piston with 2000 tons then to get the water to
freeze I must chill it down to -2 celsius.