Physics Demo -- Superconductor

Back


A bismuth-based superconducting disk sits on a copper base and is immersed in liquid nitrogen. Two small, very strong magnets are placed on top of the superconductor. The magnets levitate due to the expelled magnetic field from the superconductor.

Superconductors have the unique property of providing zero resistance for electrical currents when cooled to low enough temperatures. Thus, a current induced in a superconductor will last for an extraordinarily long time. This property also leads to the fact that superconductors will expel all magnetic fields, a phenomenon called the Meissner Effect. As a result of this effect, a magnet approaching a superconductor will "see" an opposite magnet of the same size and field strength as itself, which causes it to levitate.
To see the original posting on MIT TechTV go to

Channel: Education
Uploaded: April 1, 2008 at 9:32 pm
Author: mittechtv

Length: 00:00:57
Rating: 4.75
Views: 5353

Tags: physics physic demo demonstration super conductor superconductor magnet mit mittechtv float levitate rise liquid nitrog

Video Comments:
RockGodZeppelin (October 11, 2008 at 12:05 pm)
comon just stick your hand in there
emeoc1 (June 24, 2008 at 7:20 pm)
Why is the superconductor placed on top of copper?
screwball3z (July 17, 2008 at 6:51 pm)
my guess is to transfer heat, as opposed to submerging the super conductor in the liquid nitrogen
MrNonsense (April 14, 2008 at 11:17 pm)
oh man that's so crazy..nothing more exciting than physics!