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Homework Help: The cause of buoyancy in terms of the molecules

  1. Jan 26, 2012 #1
    I think that buoyancy is caused by the increase of density with depth (the deeper you go, the more molecules there are per unit volume). Therefore an object in a fluid will be hit by more of the fluid molecules from below than from above (even if the difference is only a tiny fraction of 1%). Is this correct?
  2. jcsd
  3. Jan 26, 2012 #2
    Right, but the object is likely compressed more then water so the buoyancy of the object is decreased?
  4. Jan 26, 2012 #3
    It depends what the object is made out of. I just looked up water and copper and water is an order of magnitude more compressible.

    I still don't feel 100% convinced that my hypothesis in the OP is correct.
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