Why does water freeze under pressure in water jet cutting?

[capnahab]

Sirs, I have always understood that water cannot be compressed but I have been informed by competent people that it can. We use water jet cutting at 60KPSI and I am told that this water compresses by 13%. While I can accept this I do not understand why at app. 150K PSI the water freezes and that pressure is the limit. It seems to me that compressed water should gain heat and not get colder. Would you gentlemen/gentlewomen please explain? Old science nut, Bob

 

[russ_watters]

For many purposes, you assume water to be incompressible just to simplify problems, but it is actually compressible.

And yes, if you compress it it heats up, but you can then let it cool back down. Whether it freezes or not at a certain temperature and pressure depends on where that is on the phase diagram: http://www.lsbu.ac.uk/water/phase.html

 

[capnahab]

Thank you for the phase diagram. They always told me it was latent heat but I could never understand latent heat. I always thought that is was phase transistion. Too many words do decscribe the same thing.