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Wanted High density Liquid For suspension of Solids

  1. Sep 25, 2013 #1
    I want to suspend, or really have the sinking effect be slow, different kinds of rocks/ gem stones in a jar. So i don't really know where to start. I want something easy to get, clear, not toxic.
    I'm going to start with something like corn sryup and see what it looks like. But if anyone has any other ideas i would love to hear them.
  2. jcsd
  3. Sep 25, 2013 #2
    If you want a slow sinking effect you need a liquid with high viscosity, not with high density. You can probably find polymer solutions that have a viscosity that varies very strongly with temperature, that way you can "tune" how fast the rock sinks.

    A (very) high density liquid would allow your rocks to float. Liquid mercury would probably do the trick, but it is toxic and not exactly clear.
  4. Sep 25, 2013 #3
    Corn syrup is a good choice. It is about 100000 times as viscous as water.

  5. Sep 25, 2013 #4


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    To be fair, a high-density fluid would work, too. It would just be more difficult to find, especially clear in color.
  6. Sep 25, 2013 #5
    You can try solutions of various salts in water.

    The heaviest seems to be zinc chloride, you can dissolve 4.23 kg in a liter of water. It's rather corrosive and toxic however.
    You can dissolve 1.89 kg/l of caesium chloride, wich doesn't have any health problems.
  7. Sep 25, 2013 #6


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    Still, it's nowhere near the density of a rock, so such an object would still sink rather quickly.
  8. Sep 25, 2013 #7
    Various companies sell heavy liquids for separating minerals by density (google "heavy liquid" to find them). The densities of these liquids range from 2 to 4ish. Many of them are quite expensive. Many are damaging to the environment and require careful handling and proper disposal.
  9. Sep 25, 2013 #8
    Awesome... Good to know about the difference between high density and viscosity that helps. I don't what the rocks to be floating. I real was trying to get a suspended kind of effect in order to display some specimens in a unique way. You all have been real helpful thank you.
    Also here's a follow up question does a liquid's density have a direct effect on its viscosity?
  10. Sep 25, 2013 #9


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    Density affects kinematic viscosity. Dynamic viscosity is another thing.
  11. Sep 26, 2013 #10
    Ok interesting.. corn syrup offered little resistance. ..
  12. Sep 27, 2013 #11
    Here's another idea. Try Jello. Just wait until it sets some before adding the rocks.

  13. Sep 27, 2013 #12
    Granite has a density of ~2.7g/cm^3, so dissolving >1.7kg of a salt would make the solution more dense than a granite rock.
    Other minerals may have different density, most seem to be more dense - pyrite is already up at 4.9g/cm^3.
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