Levitating Magnetism: Understanding the Science Behind Magnetic Levitation

  • Thread starter Thread starter Selnex
  • Start date Start date
  • Tags Tags
    Magnetism
AI Thread Summary
The discussion centers on the phenomenon of magnetic levitation, particularly involving superconductors. Observers describe seeing a superconducting disk with a magnet levitating above it, attributed to the expulsion of magnetic fields from the superconductor, which allows the magnet to float if the repulsive force exceeds gravity. The conversation also touches on the idea that while non-magnetic objects can be levitated, they cannot be turned into magnets; rather, they can exhibit magnetic properties under strong magnetic fields. Examples include frogs and spiders levitating due to induced magnetic fields or coatings. The use of liquid gases, likely liquid helium, is mentioned as a coolant necessary for superconductors to function at low temperatures. The phenomenon is explained through the principles of electromagnetism, where all matter has some magnetic potential, allowing for levitation under the right conditions.
Selnex
I have seen what I seem to remember a disc made of super conducting material levitating over a substance I seem to remember as some form of liquid gas. Is there anyone who could please clue me into what I was observing and how it operates? Does what I observed somehow relate to opposing forces of magnetic poles or some other aspect of magnetism.

Also concerning levitation and magnetism, I have seen a scientific documentary with the subject matter of magnetism. It showed how with enough energy anything could be magnetized. A spider, magnetized apparently, levitated and was floating around within a small area that was encased in circle of what appeared to be some type of metallic material. Can anyone please explain to me what it means or how it is so that any object, using enough energy can be essentially turned into a magnet and how it occurred that these normally non-magnetic objects could be floating.
 
Physics news on Phys.org
Hi,
You most likely saw a superconducting disk with a small magnet floating above the disk. A superconductor does not have any magnetic field inside of it (well to a good approximation). The magnetic field from the small magnet can't penatrate into the superconductor. There is a force expelling the magnetic field (Pushing the magnet up) if this force is larger than gravity then the magnet floats above the SC disk.

You can't turn anything into a magnet. I've seen frog and bees levitating, but I can't remember how this was done. Magnetic fields are porduced inside the frogs and other animals. Now if the frog is light enough these fields might be large enough to levitate the frog. Or you might be able to coat the frog with a very thin layer of magnetic material causing it to be levitated. But this method might get you into trouble with animal cruelty people.

JMD
 
Was the "liquid gas" that you saw giving off a great deal of steam or fog? That would make it almost certain that what you saw was, as nbo10 stated, a superconductor. More specifically, a superconducting electromagnet. If that is the case, then the liquid itself was not generating the magnetic field. It was merely being used as a coolant. Superconductors only function at very cold temperatures, and typically use liquid helium to stay frosty.

You can get some good information, and a diagram that may be of the device you saw http://cseserv.engr.scu.edu/nquinn/ENGR300Winter2001/researchprojects/DRummler/RUMMLER-SUPERCONDUCTING-FINAL.html

I saw the show with the floating frogs, spiders, plastic Mickey Mouse, etc., and I believe the point was not that anything can be made into a magnet, but rather everything has some magnetic potential. All objects that are made of atoms have electrons in them and, given a strong enough magnetic field, anything will levitate.
 
Last edited by a moderator:
Yeah I saw that one too.

I read that the magnet both floated and spun around because the super cooled metal generated large EMF's
 
You have to start the magnet spinning and it will continue to spin for quite some time, because the friction is very low. EMF is produced on the surface of the SC but not in interior, to repel the magetic field from the magnet.

JMD
 
This is from Griffiths' Electrodynamics, 3rd edition, page 352. I am trying to calculate the divergence of the Maxwell stress tensor. The tensor is given as ##T_{ij} =\epsilon_0 (E_iE_j-\frac 1 2 \delta_{ij} E^2)+\frac 1 {\mu_0}(B_iB_j-\frac 1 2 \delta_{ij} B^2)##. To make things easier, I just want to focus on the part with the electrical field, i.e. I want to find the divergence of ##E_{ij}=E_iE_j-\frac 1 2 \delta_{ij}E^2##. In matrix form, this tensor should look like this...
Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'
Please can anyone either:- (1) point me to a derivation of the perpendicular force (Fy) between two very long parallel wires carrying steady currents utilising the formula of Gauss for the force F along the line r between 2 charges? Or alternatively (2) point out where I have gone wrong in my method? I am having problems with calculating the direction and magnitude of the force as expected from modern (Biot-Savart-Maxwell-Lorentz) formula. Here is my method and results so far:- This...
Back
Top