It also helps to reduce stray fields around the magnet so mechanical watches and the like don't get ruined.
Bob at PC
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From: phys-l-bounces@carnot.physics.buffalo.edu [phys-l-bounces@carnot.physics.buffalo.edu] on behalf of John Denker [jsd@av8n.com]
Sent: Thursday, August 25, 2011 4:58 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] magnet keepers
On 08/25/2011 01:49 PM, Bernard Cleyet wrote:
Does a keeper keep (physics myth?),
Sometimes, yes. It is not a myth.
and if so, why?
"Why" is almost certainly the wrong question.
If you meant to ask "how is that related to other stuff we
know", then the answer is simple: It lowers the energy of
the system, making it unconditionally stable, as opposed
to metastable.
In some cases the metastability is so robust that no keeper
is needed, while in other cases the keeper demonstrably helps.
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