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Lifting power of Compressed Air

  1. Jun 7, 2008 #1

    Question: Is the Lifting Power of Air in Water solely based on its Volume or does the pressure of the Air factor in?

    As an example, in Salt water if you have a Bell with 2 Cubic ft of Air in it, at the Oceans Surface it can lift 128 Lbs, because air can lift the amount of Water it displaces, which in this example is 2 Cubic Ft and Salt water is 64 Lbs/Cubic ft. so it can lift 128Lbs.

    But what happens if you bring that Bell down to 33ft (1 Atmosphere), which will compress the Air to 1/2 its Volume, so at 33ft the Volume of the Compressed Air will now be 1 cubic ft. Would that Bell now only be able to lift 64 Lbs?

    What happens if you bring that Bell to 99ft deep or 4 Atmospheres, the Volume is now 25% of its Volume at the Surface, so that same Bell can now only lift 32Lbs?

    If that logic holds true in the Ocean, do any of those calculations change if the same Bell is placed in a 100ft Cylindrical Water Tower filed with Salt Water placed on the Ground at Sea Level?

    Thanks for any Input.
  2. jcsd
  3. Jun 7, 2008 #2


    User Avatar

    Staff: Mentor

    Welcome to PF.

    You understand the issue perfectly... so the answer to your your last question is no.
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