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Floating and Sinking in a Liquid

  1. Jul 23, 2013 #1
    This seems to be a relatively simple question, yet I'm not sure of the answer.

    A balloon filled with helium gas floats in air. If I submerged a balloon or container in a liquid (e.g. water), is there a liquid with which I can fill the container so as to make it float to the surface. What kind of a liquid would this be? What kind of properties must it have in relation to the water? Specifically this liquid should be the reason the container floats - without the liquid the container sinks.

    Looking forward to your responses.
  2. jcsd
  3. Jul 23, 2013 #2


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    Staff: Mentor

    What would be in the container if the liquid were not in it? Air? Hard vacuum? The same material that the container walls are made of?
  4. Jul 23, 2013 #3
    Anything that would make it sink.

    Essentially my question is...if I have a (lets say metallic container) is there a liquid that can make the container float in water (or other liquid)?

    Basically, what relation between the two media mentioned above (that dont include air) determines whether or not the container will float?
  5. Jul 23, 2013 #4


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    Homework Helper

    If the container is light enough, then any liquid less dense then water would result in the container floating, such as ethanol.
  6. Jul 23, 2013 #5
    Whether or not an object, any object, will float or not in a medium depends on the density (mass/volume) of the object as well as that of the medium. If the density of the object is lesser than that of the medium, it will float. If greater, it will sink. If the densities are equal, the object will remain where it is.

    If your container is sinking without any liquid in it, it's density is more than the density of water. In that case, no liquid you fill can make it float. It will always sink.
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