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From: cpf@batcomputer.tn.cornell.edu (Courtenay Footman)
Newsgroups: sci.electronics,sci.physics
Subject: Re: superconductor recipes wanted
Message-ID: <3849@batcomputer.tn.cornell.edu>
Date: 25 Feb 88 00:49:19 GMT
References: <20175@amdcad.AMD.COM> <193@conexch.UUCP> <633@pasteur.Berkeley.Edu>
Reply-To: cpf@tcgould.tn.cornell.edu (Courtenay Footman)
Organization: Cornell Theory Center, Cornell University, Ithaca NY
Lines: 30
Keywords: supercondutor demo kit

In article <633@pasteur.Berkeley.Edu> svv@cory.Berkeley.EDU.UUCP (Nobody in Particular) writes:
>In article <193@conexch.UUCP> root@conexch.UUCP (Larry Dighera) writes:

>> ...The only additional
>>material needed is liquid nitrogen to cool the disk for demonstrating
>>the Meissner effect, in which a superconducting disk can be floated
>>over a magnet.  

>WOW! The disk can be floated over the magnet!! That's a real strong
>magnetic field!!

>(Actually, methinks the magnet floats over the disk, but what do I
>know? I'm not a physics major...)


Here is a diagram of the experiment:

                          O
                      \_______/
                       
O can be a magnet and float over a superconducting dish, or it can be
a superconductor floating over a magnetic dish.  Since it is easier to 
make a large magnet than a large superconductor, one usually has the 
supercondutor float over the magnet.  The magnetic field required for a 
given distance is the same in both cases.

-- 
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