Mwater g(H+h) If you have a column of water 100 meters tall (10 atm) and you insert an object in at the bottom of the column you have to use enough energy to displace the volume of the object. The pressure times the volume is your energy requirement: correct? But suppose you were able to put a solid barrier between the top of the water at a height of only 10 meters (1 atm). None of the pressure of the upper 9 atm is allowed to transfer into the bottom 1 atm environment. Would the energy requirement to insert the object be the volume times 10 atm or 1 atm? Are you violating the Law of Conservation of Energy if you say 1 atm? Why or why not?