Superconductors – Meissner effect
A magnet levitating, “pinned” above a 1 inch disk of Yttrium, Barium and Copper superconductor in a pool of liquid Nitrogen at -196C. This is the “Meissner” effect.
“Continue reading” for further demonstrations. 4 photos and animation plus links…
An exposed cold object exposed to air will develop frost and water crystals. Generally it is thought best not to touch very cold things.
The little NIB magnet is iced over here as it cools with added liquid Nitrogen. As it cools the magnetic field is expelled. It levitates up off the YBCO superconductor disc.
This is the true Meissner effect and is different to magnetic induction next to a perfect conductor. Superconductors are not just perfect conductors or the Meissner effect would not happen.
The spin is due to the asymmetrical lift and lack of friction when it is levitated. This is the basis for a frictionless magnetic bearing which self centres and apparently achieved up to 1 million rpm.
Liquid Nitrogen is supplied in a Dewar which is a steel Thermos like flask. It has a non occluding cap with a sponge plug.
The superconducting kit is from Colorado Superconductor Inc.
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External links
Meissner effect -Wikipedia
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Photo Date: May 14, 2012