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| Science Forum Index » Physics - Electromagnetic Forum » Magnet toy... |
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| Maxon Buscher... |
 Posted: Fri Nov 06, 2009 4:58 pm |
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Guest
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This may not be the most appropriate group for this but here goes.
I want to make a toy that starts with say 100 empty medicine capsules,
each one containing a tiny and loose steel ball. All the capsules
will be placed
in a glass bowl covered with a glass sheet. An external magnet, motor
driven, will
cause the capsules to flip and roll and tumble. Problem - the steel
balls may eventually
become magnetized and then begin stick together, ruining the kinetic
display.
Is there a kind of steel that does not acquire such permanent
alignment of its
domains? Any suggestions would be appreciated.
Thanks
Max Buscher
lofting at (no spam) ttlc.net |
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| Salmon Egg... |
| Posted: Sat Nov 07, 2009 12:34 am |
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Guest
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In article
<4cda1e32-e7f9-4c64-b53c-2c1161de5fc0 at (no spam) r24g2000yqd.googlegroups.com>,
Maxon Buscher <lofting at (no spam) ttlc.net> wrote:
[quote]This may not be the most appropriate group for this but here goes.
I want to make a toy that starts with say 100 empty medicine capsules,
each one containing a tiny and loose steel ball. All the capsules
will be placed
in a glass bowl covered with a glass sheet. An external magnet, motor
driven, will
cause the capsules to flip and roll and tumble. Problem - the steel
balls may eventually
become magnetized and then begin stick together, ruining the kinetic
display.
Is there a kind of steel that does not acquire such permanent
alignment of its
domains? Any suggestions would be appreciated.
Thanks
Max Buscher
lofting at (no spam) ttlc.net
[/quote]
You want soft iron balls. The terms hard (for permanent) and soft for
transient magnetization can be taken literally. Dislocations and
impurities that form hard steel makes it difficult for steel to form
into permanent magnets and for permanent magnets, once formed, to
demagnetize.
To summarize, you want pure annealed iron. Maybe wrought iron could do
the job.
Bill
--
As the years go by, dying just before having to fill out a tax return has merit. |
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| whit3rd... |
| Posted: Fri Nov 13, 2009 10:12 am |
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Guest
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On Nov 6, 9:34 pm, Salmon Egg <Salmon... at (no spam) sbcglobal.net> wrote:
[quote]In article
4cda1e32-e7f9-4c64-b53c-2c1161de5... at (no spam) r24g2000yqd.googlegroups.com>,
Maxon Buscher <loft... at (no spam) ttlc.net> wrote:
... Problem - the steel
balls may eventually
become magnetized and then begin stick together, ruining the kinetic
display.
You want soft iron balls.
[/quote]
And, they're easily available, by the pound (as shotgun or BB gun
loads).
It's possible they'll clump anyhow, because the applied magnet
field will both move the balls AND cause them to attract each other. |
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