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Bouyancy issue

  1. Mar 11, 2010 #1
    If a rubber ball is fill with air, attached to a cord and pulled under water, I assumed it collapses under pressure at some rate. The question is, will it at some point lose enough bouyancy to sink to the bottom?
  2. jcsd
  3. Mar 11, 2010 #2

    only if the material is denser than water....
  4. Mar 11, 2010 #3
    Prolate steel spheroids, like the USS Thresher, will collapse when the water pressure exceeds its design pressure, and sink to the bottom. See


    Bob S
  5. Mar 11, 2010 #4
    Liquid carbon dioxide is more compressible than water, and undergoes a similar phenomenon:
  6. Mar 11, 2010 #5


    Staff: Mentor

    I heard once that dolphins use this to be able to efficiently dive deep. They go deep enough that their lungs collapse sufficiently that they become negatively buoyant and can just drop down to their desired depth.
  7. Mar 11, 2010 #6
    Just to clarify and make sure I understand, upon having their lungs collapse, the reason they are able to sink lower is because they are more dense than the water under them.

    Am I right?
  8. Mar 12, 2010 #7


    Staff: Mentor

    Yes, although I just vaguely remember reading that in a pop-sci journal so it is not a reliable reference or anything.
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