Show Me Some Science! Quantum Levitation
A magnet is placed in the air above a superconductor and it just stays there like magic. But it’s not magic, it’s science. Check out all of the awesome experiments we can do!
What’s a Superconductor?
All metals become better at conducting electricity and heat as they are cool. There are other materials out there that behave differently. When they get cold enough, they actually go through a phase transition, and become a perfect conductor of electricity, with zero electrical resistance. These materials are called superconductors.
Superconductors and Magnetic Fields
When a magnet is moved near a superconductor, an electrical current is induced in the superconductor. This electrical current creates it’s own magnetic field opposite of the magnet which repels the magnet and cancels out the magnetic field due to the magnet. This is an extreme example of diamagnetism (see our Magnetic Levitation Shopcast).
The lack of a magnetic field inside of a superconductor can explain the levitation, but a magnet can also hang from the bottom of the superconductor. This is because in some (Type 2) superconductors, a strong magnetic field can actually get through in discreet tubes called “flux tubes”. What’s actually occurring is that the superconductivity is destroyed within the tubes, which lets the magnetic field through. At low temperature, the flux tubes get pinned into place in the areas where the superconductivity is the weakest. This is what “locks” the magnet into a specific position and orientation relative to the superconductor.