PURPOSE: To show the Meissner effect.
DESCRIPTION: A superconductor is cooled with liquid nitrogen to a temperature below its Critical Temperature,
Tc. When cooled to zero resistance the superconductor will not allow any magnetic field to
freely enter it. A small permanent magnet is placed on top of the
disk of superconductor material. The magnetic field of the magnet is
repelled, and the magnet levitates. This can be seen quite dramatically by a
carefully positioned video camera.
The magnet itself is repelled, and thus is levitated above the superconductor. For this experiment to be successful, the force of repulsion must exceed the magnet's weight. This is the case for the small, rare earth magnet used in the demo. Don't lose the magnet!
EQUIPMENT: This demo kit can be purchased from Colorado Superconductor, and some very good references can be found at the web site.
SETUP NOTES: See below:
Position the video camera close to the object, use a white background and a bright front lighting, and stop down the aperature for deep depth of field.
