# Pressure to freeze ice

1. Feb 27, 2015

### Calpalned

1. The problem statement, all variables and given/known data
**This thread could also belong to the chemistry forum**
*This isn't an actual homework problem, but it is a simple question, so I put it here in the homework forum. I am under the impression that the physics forum is for more advanced questions*
How deep would an ocean on earth have to be for ice VII to form? It forms under 3 GPa of pressure at room temperature (20 C).

2. Relevant equations
N/A

3. The attempt at a solution
I am only asking this question because I am curious how the Mariana Trench compares. At the bottom of the Mariana Trench, the pressure is 110 MPa. $\frac {3} {t} = \frac{3GPa}{110MPa}$ = 27.27. So the Mariana Trench needs to be 27 times deeper. Is this correct (if the temperature is assumed to be a constant ?

2. Feb 27, 2015

### Bystander

Give or take corrections for compressibility of sea water, looks good enough. Depth of Mariana Trench isn't a particularly standard unit of length, so you might consider turning that into meters or kilometers, but that's nitpicking.