Don Burke:
incorrect Blow up a balloon at sea level and take it to one thousand feet. It is no longer 1atm.Actually, a rigid container sealed at depth will continue to hold (or attempt to hold) the pressure.
You've built a house of cards based on density change and it caves in when the density change is not available. There's a message there. Your initial premise is flawed.
Yes, I know and agree with the whole balloon thing. The wall of the balloon is not rigid so it will expand. The pressure inside the balloon will always equal ambient.
Is Don and Big-T saying that water pressure can be stored????? This is nonsence, if it weren't you would be warned not to drink any *high pressure* water at depth because your bladder could rupture on the way up (leading to the 2nd rule of diving, always pee continuously).
If I fill a rigid container at depth (regardless of shape), a pressure gauage inside the container will always read ambiant pressure!!! Can't we think of people as containers of fluid? If my fluids are at 1 atm at the surface and are still 1 atm at depth, I would be crushed.
Numerical density (and temperature) being the direct cause of air pressure (regardless of how that density was *formed* be it by gravity or an air compresser) is fundemental to the gas laws. Knowing the numerical density and temperature of a gas, I can actually calculate the pressure of the gas (the ideal gas law, p = n/V * RT, n/V being number of molecules per volume - numerical density, R being a costant and T being the temperature absolute).
All of the other gas laws can be simply derived from the ideal gas law (also know as the equation of state for ideal gasses).
Don, you are confusing filling a container of water at depth and a container of air at depth. Water brought up in a rigid container from 5000 feet will not be under pressure. How do they bring up specimin bottles from extreme depth? Do theu have to put in extremely strong containers? When they open the lid, what happends? Does all of that high pressure water escape. Make sure that when you a are pumping water out of a well that you don't get the high pressure water from the bottom of the well
I'm done arguing the whole bringing up water from depth, if anyone believes the pressure inside the container is constant and doesn't always reflect ambient pressure, I won't be able to convince them without the doing a test - take a soft walled container (such as a balloon) to 33 feet, let some water in it (no air), tie it off and then come to the surface, has the balloon expanded to twice its size? No, it hasn't therefor the water pressure can't be stored (try it with air, you will find that the balloon has expanded).