Hey, is there an equation to work out what the pressure is at given depths under water? Basically, I have a set of results showing the volume of 'some' air increasing as the pressure is changed. I know that pressure x volume is constant. I need the above equation to explain how my results occured. (as well as to see how accurate my experiment was)! One thing that I have been told that the pressure increases by 1 atmospheric pressure unit every 10m under water, however I dont know what the magnitude of the atmospheric pressure unit is in terms of pressure (to be used in the pV = nRT equation). My guesses from what i've been told is that... Pressure = 1/10 * depth (in meters) * atmospheric pressure unit Any help would be greatly appreicated, thanks!