Talk:Diamagnetism

message: https://www.nde-ed.org/EducationResources/CommunityCollege/MagParticle/Physics/MagneticMatls.htm#:~:text=Most%20materials%20can%20be%20classified,negative%20susceptibility%20to%20magnetic%20fields.&text=Paramagnetic%20materials%20have%20a%20small%2C%20positive%20susceptibility%20to%20magnetic%20fields.
really ,re write using this as template  — Preceding unsigned comment added by 50.245.17.105 (talk) 19:49, 30 December 2020 (UTC)
thread_title: much better explanation, pitched at the right level

message: someting is very wrong with the description of diamagnetism, "causes it to create a magnetic field in opposition to an externally applied magnetic field, thus causing a repulsive effect", this repelling is because the diamagnet is less permeable than air and so the flux desires to go around the diamagnet (easier to go through the air than through the material) which causes the repelling effect.  (simular to superconductor Meissner effect) there is an expiriment that demos this by hanging a small bar of glass or a small bar of aluminium between magnet poles the bars align themselves if they are diamagnetic or paramagnetic (Al).information source: http://www.henschke-geraetebau.de/english/Electromagnetic-experiment-apparatus.pdf   article should address whichever view is a misconception. finally, shouldnt lenz law repelling cease after magnetism has peaked? and a possible expiriment to confirm is to increase the air pressure, if the reflection on the water is further distorted then the water is not being repelled by the magnet but instead displaced by air. Charlieb000 (talk) 23:33, 19 February 2011 (UTC)
thread_title:  possible inaccuracy 

message: I edited the third paragraph to exclude helium. Helium only contains S-shell electrons which have no angular momentum and thus cannot be effected by magnetic fields. Beryllium and magnesium, in their metallic state, have P-shell states which overlap with the S-shell electrons and thus can be paramagnetic at temperatures greater than 0K.  —Preceding unsigned comment added by 149.169.54.225 (talk) 20:39, 31 January 2008 (UTC)
thread_title:  Helium 

message: I think this article can't be complete until we find a free image of a levitating frog! I'll have a hunt... OK managed to get permission from Nijmegen High Field Magnet Laboratory. CharlesC 14:31, 19 December 2005 (UTC)
replies: text: I think anything that did would have to be Klein bottle-shaped  —Preceding unsigned comment added by Tar7arus (talk • contribs) 20:29, 30 August 2009 (UTC)
thread_title:  Levitating frogs 

message: (Mouvement, 22 Jan 2005)
At the end of the article page, there is a description on how to make a diamagnet leviate. Does anyone know the reason, why this is stable?
I just clarified it, let me know if it does or doesn't make sense.Pkeck 18:54, 6 May 2005 (UTC)
thread_title:  Explaining the leviation experiment 

message: Can you insert a table of diamagnetic materials?
i.e.
Bismuth -16.6 
Mercury -2.9 
Silver -2.6 
Carbon (diamond) -2.1 
Carbon (graphite) -1.6 
Lead -1.8 
Sodium chloride -1.4 
Copper -1.0 
Water -0.91 
etc...
:Almost everything is diamagnetic.  Many metals are para-, a few are ferro-, but dia- is the most common, especially given the wide variety of organic materials.  BTW, you forgot the exponents.  But here are a few more entries, from Halliday, Resnick, & Krane ():
:Bismuth -1.7 (you have 1.66, which I'll accept) e-5
:Mercury -3.2 e-5 (different from yours by ~10%, but HR&K sucks as physics books go)
:Silver -2.6  e-5
:Carbon dioxide (STP) -1.1  e-8
:N2 (STP) -5.4  e-9
:And from this site:
:Material	 χv / 10-5
:Ammonia	-1.06
:Bismuth	-16.7
:Copper	-0.92
:Hydrogen	-0.00022
:Silicon	-0.37
:Water	-0.90
:Enjoy.  --Joel 05:53, 12 May 2005 (UTC)
replies: text: PS: Whatever compilation table ends up coming together, we should probably mention that the values are volumetric & dimensionless.
---- I'm not sure why, but the table I got looks like this: 
*Material 2 x(31026)
*Water 8.8
*Bismuth metal 170
*Graphite rod 160
*Pyrolytic graphite ' axis 450
*Pyrolytic graphite i axis 85
Tell Me Why!!
----
This table gives a mu for superconductors of -1E5, but the text says that it should be -1. --Belg4mit (talk) 22:23, 18 April 2011 (UTC)

text: Never mind, I see that this is to counteract the 1E-5 applied to the table as a whole. It's still potentially confusing and inelegant though. --Belg4mit (talk) 22:35, 18 April 2011 (UTC)
thread_title:  Diamagnetic materials table 

message: I re-added the cleanup and accuracy tags. The tone of the whole article is very informal and inappropriate and there are egregious factual inaccuracies in the superconductor/MRI explanations (for starters). A physicist (or at least someone who really knows what they're talking about) is badly needed to clean this article up. --Deglr6328 04:29, 29 September 2005 (UTC)
replies: text: You're not the first to say that, and yet no one gives any examples of what they think is wrong.  I don't see any informal tone or factual errors.  — Omegatron 13:45, 29 September 2005 (UTC)
replies: text: The diamagnetic levatation section reads like a science fair project when it should actually be a lucid explanation of the physics behind said phenomenon and after that should come a demonstration section. --Deglr6328 23:19, 29 September 2005 (UTC)
replies: text: Also, in the diagram of the suspended magnet, field lines cross. Field lines NEVER cross. I do not have the means to fix this mastodon 21:55, 26 November 2005 (UTC)
thread_title: Major Cleanup Needed

message: Sorry for this being a bit off topic, but I couldn't think of a better place to ask:
Using no special equipment, is there any way to demonstrate diamagnetism of water with just a standard magnet?
My ideas were things like putting a magnet into a fine mist, and watch for changes in the density of the mist.  Would that work? —The preceding unsigned comment was added by Wierdy1024 (talk • contribs) 23:13, 7 December 2006 (UTC)
replies: text: A common demonstration of this is to put a very strong NIB permanent magnet (N45 or more if you can find it, and a half inch or more across) at the bottom of a petri dish, and add just enough water to slightly cover the magnet. Google shows several sites with photos of this, such as http://www.matchrockets.com/water/diamagh2o.html ... --Splarka (rant) 08:10, 8 December 2006 (UTC)
thread_title:  Effect of diamagnetism on water 

message: There is a source that can be cited for the last paragraph in the entry:
http://www.unitednuclear.com/magnets.htm
The second last section on that page is about Diamagnetism and a bismuth display setup kit. 143.117.120.104 (talk) 09:21, 16 January 2008 (UTC)
thread_title:  Diamagnetism in the home 

message: The article states, confusingly, that superconductors may be viewed as perfect diamagnets.
However the origin of their magnetization opposing the applied magnetic field is completely different from that of ordinary diamagnets.
While in an ordinary diamagnet, such as water, the opposing field is caused by eddy currents. In superconductors it is caused by electron-lattice interactions (cooper pairs).
I've added this note to the sentence.
A superconductor acts as an essentially perfect diamagnetic material when placed in a magnetic field and it excludes the field, and the flux lines avoid the region
Superconductors may be considered to be perfect diamagnets (\ \chi_{v} = −1), since they expel all fields from their interior due to the Meissner effect.
Changed to:
A superconductor acts as an essentially perfect diamagnetic material when placed in a magnetic field and it excludes the field, and the flux lines avoid the region
Superconductors may be considered to be perfect diamagnets (\ \chi_{v} = −1), since they expel all fields from their interior due to the Meissner effect.
However this effect is not due to eddy currents, as in ordinary diamagnetic materials, see the article on Superconductivity.
--Jaapkroe (talk) 16:40, 18 September 2009 (UTC)
thread_title:  superconductors are not diamagnetic! 

message: should we get into more detalied QM explaination for how the property arise in the first place in this article?  —Preceding unsigned comment added by ArielGenesis (talk • contribs) 20:36, 9 June 2010 (UTC)
thread_title:  quantum mechanical explenation 

message: "Diamagnetism is the property of an object which causes it to create a magnetic field in opposition to an externally applied magnetic field...." This is correct, but it doesn't tell you that:
*"Diamagnetism is the property of an object which causes it to create a magnetic field in alignment to an externally disapplied magnetic field...."
The cause of diamagnetism is the effect that Lenz's law has on underlying spin currents of matter. Diamagnetism involves resistance to the changes in the magnetic field, and thus diamagnetic materials repel incoming magnetic fields and attract outgoing magnetic fields. This explains why supercooled diamagnetic materials will levitate on a magnetic rail without falling off even when the rail is flipped upside down (click here for examples).siNkarma86—Expert Sectioneer of Wikipedia86 = 19+9+14 + karma = 19+9+14 + talk 21:16, 12 April 2011 (UTC)
replies: text: Superconductors don't merely oppose changes in the magnetic field. They expel any magnetic field that is in the body before it becomes superparamagnetic. RockMagnetist (talk) 13:20, 13 April 2011 (UTC)
replies: text: How is "expelling" magnetic fields mathematically different than subtracting out, in its entirety, the magnetic field (whether pre-existing or not) cutting through the body? I think that any real magnetic field will not be perfectly constant, even in a superconductor, so any increases in the conductivity would seem to act against any magnetic field changes inside the body by allowing Lenz's law to take effect more rapidly, allowing charges to become responsive even to very small fluctuations in the magnetic field, and thereby "deleting" many of the magnetic fields inside the body.siNkarma86—Expert Sectioneer of Wikipedia86 = 19+9+14 + karma = 19+9+14 + talk 21:46, 13 April 2011 (UTC)
replies: text: Kmarinas, you're speculating, and plausible as your speculations sound, they're wrong. Superconductivity is a quantum effect.RockMagnetist (talk) 00:08, 14 April 2011 (UTC)
replies: text: Where did I say that it wasn't a quantum effect? Isn't a superconductivity subset of diamagnetism?siNkarma86—Expert Sectioneer of Wikipedia86 = 19+9+14 + karma = 19+9+14 + talk 00:37, 18 July 2011 (UTC)
thread_title:  The other side to diamagnetism 

message: This whole article is horrible. It was clearly not written by a competent physicist. The mixing of classical Lenz's law statements with Quantum mechanical ideas is childish. Then, the author throws is a description of what fields lines are doing !!! Field lines are NOT Real - they thus do not move. They are a mathematical description. In many classical cases deducing physics from field line 'motions' leads to the wrong answer. This article is such crap that it should be removed in its entirety as it trashes basic physics. Leave physics to physicists. — Preceding unsigned comment added by 165.201.140.13 (talk) 15:42, 20 February 2012 (UTC)
replies: text: Your objections seem to apply mainly to the lead paragraph (which I agree needs rewording) and a figure. Do you disagree with any other part of the article? Wikipedia authors have many authors. If you don't like the way this article is written, you could edit it. RockMagnetist (talk) 17:42, 20 February 2012 (UTC)
thread_title: Bad Article

message: :Earnshaw's theorem seems to preclude the possibility of static magnetic levitation. However, Earnshaw's theorem only applies to objects with positive moments, such as ferromagnets (which have a permanent positive moment) and paramagnets (which induce a positive moment).
Is Earnshaw's theorem even relevant? From what I gather, it only applies in the absence of other forces. For example, take a glass cylinder, and put in two permanent magnets of an opposite orientation, of the same size as the cylinder's diameter. The second magnet will levitate above the first (the magnetic force offsetting the Earth's gravity), and won't be able to move sideways because of the cylinder. - Mike Rosoft (talk) 10:25, 7 July 2012 (UTC)
thread_title: Magnetic levitation

message: perhaps we could add a section that explains how diamagnetism is affected by electron configurations? maybe something like this?  — Preceding unsigned comment added by 173.16.173.3 (talk) 01:36, 2 December 2014 (UTC)
thread_title:  Section on Electron configurations 

message: Hello fellow Wikipedians,
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thread_title:  External links modified 

message: this needs to be included68.151.25.115 (talk) 09:14, 15 June 2017 (UTC)
replies: text: I have corrected and expanded the existing note at the bottom of the lead. RockMagnetist(talk) 15:26, 15 June 2017 (UTC)
thread_title:  etymology