Can a magnetic field defy gravity?

[shihab-kol]

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?

 

[Copernicus45]

Yes, it is possible. If I think the Magnetic force equals the pull of gravity.

 

[davenn]

Is it possible to make them hang in the air against gravity with a sufficiently strong magnetic field?

have you not seen those toys that do that ?

Dave

 

[Drakkith]

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?

Yes, it is possible. If I think the Magnetic force equals the pull of gravity.

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.

 

[CWatters]

Video showing a strong magnetic field picking up some rather large "filings"...

 

[shihab-kol]

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.

Why is passive magnetic levitation unstable?

 

[CWatters]

See .

https://en.m.wikipedia.org/wiki/Earnshaw's_theorem