

Is Aluminum Magnetic? (2013) - zeeshanm
http://terpconnect.umd.edu/~wbreslyn/magnets/is-aluminium-magnetic.html

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dkhar
On the subject of interesting magnetic effects, a lot of people don't know
that pretty much all matter is magnetic, just that the strength of the
interaction is a lot smaller than what we're used to with ferromagnets.

All materials exhibit a diamagnetic (pushes against the field) effect, but in
many materials, that effect is overwhelmed by a competing paramagnetic (pushes
in the direction of the field) effect. Most of the things we call "magnets"
exhibit ferromagnetism, which typically produces much stronger forces than
either of the previous two.

H2O is particularly interesting, because it's actually diamagnetic, and will
push away from magnetic fields. Given a strong enough magnet, you can have a
lot of fun with this effect by putting common water-filled objects in its
field:
[http://www.ru.nl/hfml/research/levitation/diamagnetic/](http://www.ru.nl/hfml/research/levitation/diamagnetic/)

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snarfy
Another fun fact: Magnetic fields are a consequence of relativity and length
contraction of electric fields.

[http://physics.weber.edu/schroeder/mrr/MRRtalk.html](http://physics.weber.edu/schroeder/mrr/MRRtalk.html)

This video also talks about it:
[https://www.youtube.com/watch?v=1TKSfAkWWN0](https://www.youtube.com/watch?v=1TKSfAkWWN0)

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hrjet
Nitpick: relativity can _explain_ magnetism, not _cause_ magnetism.

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snarfy
True, it explains them in terms of electric fields, but we still don't know
what those are.

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readerrrr
We know:

[http://en.wikipedia.org/wiki/Electric_field](http://en.wikipedia.org/wiki/Electric_field)

[http://en.wikipedia.org/wiki/Electric_charge](http://en.wikipedia.org/wiki/Electric_charge)

[http://en.wikipedia.org/wiki/Quantum_electrodynamics](http://en.wikipedia.org/wiki/Quantum_electrodynamics)

 _An electric field is generated by electric charge and time-varying magnetic
fields_

 _Charge is the fundamental property of forms of matter that exhibit
electrostatic attraction or repulsion in the presence of other matter.
Electric charge is a characteristic property of many subatomic particles._

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danbruc
Nitpicking again - the fields are a working mathematical description but, as
far as I know, we don't know if or in what sense they are real things,
whatever real thing even means. The electrical and magnetic fields change when
you switch reference frames, so that does not sound like something that really
exists independent of an observer. The vector potential on the other hand does
not change but it does not seem real either because it has gauge symmetry.

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snarfy
We know that the A field is more fundamental (at least Feynman thought so):

[http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect](http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect)

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pranjalv123
I don't think any of these examples actually imply anything about whether
aluminum is "magnetic" (for any definition of magnetic).

All the demonstrations rely on a changing magnetic field, either because the
magnet is moving, or because the aluminum is moving. This induces an electric
field in the aluminum (as it would in any conductor) which moves the aluminum,
induces a magnetic field which moves the magnet, etc., but is independent of
whether aluminum is ferromagnetic, paramagnetic or diamagnetic.

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PaulHoule
I think the way to say it is that All is diamagnetic.

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k_sze
Too bad the videos are not done by Bill Nye.

Electromagnetics is awesome, nonetheless. :)

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delbel
you mean AL-e-um? (w/ British overtone.. :)

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JonRB
The one thing I really took away from this (and unfortunately not entirely
relevant) is that American English also has it's own SPELLING of Aluminium,
not just pronunciation.

It makes the difference in pronunciation make a lot more sense to me. Are
there (m)any other cases of this, where both the spelling and pronunciation
are different? Leisure, herbs, etc.? (Lift/Elevator doesn't count)

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Hoff
[http://en.wikipedia.org/wiki/American_and_British_English_sp...](http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences#Different_spellings_for_different_pronunciations)

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JonRB
I was hoping for a bit more with regards to significant pronunciation
differences. Not just spelling differences.

