Departmental superconductor

Last year we purchased a superconductivity demonstration kit and this week saw its unveiling to our current Lower VI Form. Superconduction is a very cool (ha ha) property of certain materials where the electrical resistance of the material falls to zero when it is cooled beyond a point known as its transition temperature . They are literally super conductors. To achieve this state the superconductor needs to be cooled. Our yttrium barium copper oxide (YBCO) superconductor needs to be cooled by liquid nitrogen, which boils at −196°C or 77 K. As the YBCO transfers heat to the liquid nitrogen it cools, and once it passes its critical temperature it begins superconducting.

As the liquid nitrogen boils it cools the black superconductor. It is using heat from the superconductor to boil which is why the superconductor gets colder.

In addition to having zero electrical resistance superconductors also expel external magnetic fields, which can be seen by magnets levitating over the superconductor.

Here the silver magnet is levitating over the superconductor.

In addition, a superconductor can also trap magnetic flux lines allowing a constant separation between magnet and superconductor. This could be used in the future for super low friction bearings.

Here the magnet is spinning quite quickly; the clouds are condensing water vapour from the air.
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