GALVANÒMETRE I LEVITACIÓ MAGNÈTICA.

Hola al·lots:

Vos present dos vídeos:

- Aquest vídeo mostra el funcionament d'un galvanòmetre casero (aparell per mesurar petites corrents).




Aquest vídeo mostra l'efecte que produeix en submergir un superconductor dins nitrogen líquid i col·locar un imant damunt, anomenada levitació magnètica.



Explicació en anglès: (practise your english)

A neodymium rare earth magnet is suspended in mid air over a superconductor in a liquid nitrogen bath. The induced loop currents create dynamic magnetic fields that oppose the magnet's magnetic field that created them. My 7 year old and her two friends watch in amazement. This is what physics is all about - teaching our young. If you like testing your mind, check out the site http://www.mindchallenger.com

The black material is a superconductor ceramic. At room temperature it does not conduct, but at extremely low temperatures it has zero resistance. Superconductor ceramics have compositions consisting of oxides of barium, copper and yttrium. Other superconductors have other compositions. All of them are extremely brittle.

Saluts!

Rosa.