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Magnets, repulsion, water

  1. Dec 6, 2003 #1
    an old 'newbie' with first post. excuse my physics knowledge it has been a long time since college.
    >>>QUESTION below<<<
    Magnets repel (each other).
    If repelling 'each other' through a plane (ex. piece of glass) and water is allowed to flow over the plane.
    WHAT will happen to the water when approaches magnets that are repelling? likewise what will happen to repelling magnets?

    I would love thought/answer.
    Last edited by a moderator: Dec 6, 2003
  2. jcsd
  3. Dec 6, 2003 #2


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    Welcome Lorp!

    Just for clarity, when you say "magnets repel", do you mean two magnets that repel each other, or a set of magnets that repel water?
  4. Dec 6, 2003 #3

    magnets repelling each other.
  5. Dec 6, 2003 #4


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    As long as the water is clean, they should have almost no effect at all on one another. In the town where I grew up, the water that came out of the tap had a lot of iron in it, and that would disrupt the magnetic field between two magnets, but ordinary water shouldn't effect it at all.
  6. Dec 6, 2003 #5
    Will the water flow between the magnets?
  7. Dec 7, 2003 #6
  8. Dec 8, 2003 #7


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    If I recall correctly, water is very weakly repelled by magnets, so with sufficiently powerfull magnets, you're likely to see some effects of the water. (Possibly including no water flowing between the magnets.)

    There is a famous demonstration where a frog is floated above a powerfull electromagnet:

    http://www.hfml.sci.kun.nl/froglev.html [Broken]
    Last edited by a moderator: May 1, 2017
  9. Dec 8, 2003 #8
    Flying Frogs. Thanks!
  10. Dec 9, 2003 #9


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    And there's also the phenominon of magnetohydrodynamic drive, but I believe that in order for this to work the water has to be polarised first before passing through the magnetic field.
    Last edited: Dec 9, 2003
  11. Dec 9, 2003 #10


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    All normal matter (electrons, protons, and neutrons) interacts with a magnetic field. This is how an MRI works. There is a very intense magnetic field (~10 T) to polarize the protons. Then, there is a pulsed gradient (orders of magnitude less) that disturbs the polarization. Protons in particular configurations respond to this step excitation are different frequencies. Hydrogen, if I remember correctly, since it has only one proton, has a strong appearance, so regions with more water show up more strongly.
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