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B Magnetic field vs gravity

  1. Oct 11, 2017 #1
    If I keep iron fillings on a cardboard with a wire carrying current in some direction, I know that the fillings will orient in concentric circles.But what happens if I keep the fillings on the underside of the cardboard? Is it possible to make them hang in the air against gravity with a sufficiently strong magnetic field?
  2. jcsd
  3. Oct 11, 2017 #2
    Yes, it is possible. If I think the Magnetic force equals the pull of gravity.
  4. Oct 11, 2017 #3


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    have you not seen those toys that do that ?



  5. Oct 11, 2017 #4


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    It will not be possible to have them hang motionless in air, but it may be possible to have them attracted upwards such that they stay on the bottom side of the cardboard. The former isn't possible because passive magnetic levitation is unstable. Both of the toys shown in Davenn's post require something to stabilize them. I believe the clear plastic screen at the tip of the first toy stabilizes it and keeps it from moving forwards until it falls to the table, and I assume the 2nd toy is spin-stabilized, but I'm not certain.
  6. Oct 12, 2017 #5


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    Video showing a strong magnetic field picking up some rather large "filings"...
  7. Oct 16, 2017 #6
    Why is passive magnetic levitation unstable?
  8. Oct 16, 2017 #7


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