Viscosity Of a super fluid.

  1. If helium 4, when it is a super fluid has no viscosity then you shouldn't be able to float anything in it. And if you had a column of it you could drop a piece of wood in it and it would fall at g just like it would fall a vacuum. Am i thinking about this correctly.
     
  2. jcsd
  3. boneh3ad

    boneh3ad 1,609
    Gold Member

    No. Viscosity is not the important factor when it comes to buoyancy. You are thinking of density, and superfluid helium certainly has density.
     
  4. well I was just thinking that when people said that light moves through the ether. But then they said that the ether has no viscosity because if it did it would slow down the earth and would eventually travel into the sun. So if He-4 has no viscosity could i still drop a brick into it and have it fall at g. Or Am i wrong.
     
  5. boneh3ad

    boneh3ad 1,609
    Gold Member

    It would not still fall at g on account of the fact that drag doesn't arise from viscosity alone. However, it would fall pretty darned close to g in all likelihood.
     
  6. would it fall faster in a super fluid than in air at room temperature.
    And if I wanted to float something in a super fluid would i just use Archimedes principle.
    Would floating something in a super fluid be the same as liquid helium right before it became a super fluid?
     
  7. For the purposes of floating things, liquid and superfluid helium would be practically the same; a difference because the superfluid is colder and denser, but that's about it.


    And lets not forget it still has surface tension!
     
  8. okay i was just wondering about its bizarre properties , thanks for the answers everyone
     
  9. Superfluid really are fantastic; I was convinced for ages they were science fiction!
     
  10. ya they have very strange properties. And aren't they also super conductors.
     
  11. They are indeed! Very special things. No wonder Feynman devoted so much time to studying them!
     
  12. I have heard of people trying to make magnetic super fluids. The idea was that if the super fluid was magnetic you could accelerate it in a torus to relativistic speeds (using some sort of alternating magnetic field or something like it). This was thought to poetically make gravity waves or something. Anyone else heard of this?
     
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