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According to the 14th citation in Magnetic dipole moment Boyer, Timothy H. (1988) The Force on a Magnetic Dipole. American Journal of Physics 56 (8): 688–692. doi:10.1119/1.15501. Using the electric dipole formula for the case where the magnetic field is rotational () is not correct. Two bar magnets do have a rotational field, hence the calculation given could be not correct. The webpage cited here http://instruct.tri-c.edu/fgram/web/Mdipole.htm uses the electric dipole approximation, which according to the paper is not correct. Aslo, looking at the formula given in Magnetic moment for th einteraction of two coils when separated a big distance, shows a dependecy while, the formula given here dependos on , where stands for the distance. I guess this difference comes form the shape effect of the bar manget, but it should be verified. In the webpage where the calculations are shown this is not explained. The formula is obtained directly from the electrical analogy. -- Kakila Monday, October 26 2009 —Preceding undated comment added 15:11, 26 October 2009 (UTC).
And my the force be with you. —Preceding unsigned comment added by 82.132.19.153 ( talk) 19:41, 14 April 2010 (UTC)
Would Wikipedia consider a listing for a speculative field such as Magnetic Motors?
See: http://www.pureenergysystems.com/os/MagneticMotors/
The article ( Magnet) says
And no, i'm not about to point out that the geomagnetic field repeatedly reverses.
It's an even more pedantic issue than that, but i think i recall that what gets labelled N by convention is a north-seeking pole rather than a north pole, from which it follows that the geomagnetic pole in the northern hemisphere is a south pole. Maybe my instructor got befuddled in trying to talk about red end of the compass needle not being a north pole, but the consequences of being wrong about this are so small that 90% of confident sources could be wrong and never realize it. Does someone have a super-reliable source on this? -- Jerzy 05:50, 2003 Dec 19 (UTC)
-- Pkeck 15:10, 2005 Jan 14 (EST)
This subject tends to be confusing.
Poles, North and South Magnetic
The North Pole of a magnet, or compass, is attracted toward the north geographic pole of the Earth. If you were to use a compass to determine polarity, the South Pole of the compass will point towards the North Pole of a magnet. The North Pole of a compass is more properly called the North Seeking Pole because it seeks out the geographical North Pole. Few people take the time to say “North Seeking” Pole. If you were to use a gauss meter, using an axial probe, the side of the magnet that gives you a positive reading will be the North Pole.
North Pole = North Seeking Pole = North Magnetic Pole = Positive Gauss Meter Reading
-- Mickmark21 ( talk) 10:45, 15 October 2010 (UTC)
I started to rework this page with the hopes of making it much clearer and more organized. I feel that magnets are one of those topics that the average person might be interested in, so the content here shouldn't be too in depth. If they want more information, that's what the links are there for. If anyone sees anything that isn't clear or feels that something is missing, please help out. -- Pkeck 11:21, 2004 Jan 14 (EST)
I'm curious about this new section. First (and most importantly), is this really an accurate way to describe what's going on in a magnet? I've never heard of or thought about it this way...which isn't to say that it's wrong, I've just never heard about it. Can you point to a page with more explanation of this idea of net current flowing around the surface of the magnet? I understand exactly what you mean, I just haven't ever heard of it.
Second, is it really easier to understand why magnets attract or repel one another through this explanation? I'm thinking that if you told the average person to imagine a cylinder of current carrying loops that all had current flowing perpendicular to the long axis of the cylinder and all in the same direction...and then to imagine how the current of adjacent loops negates the flow of current in their neighbors because they are flowing in opposite directions at adjacent points...which means that there will only be a net flow around the surface of the cylinder...I'm thinking the average person would be completely lost.
To be honest, it seems much more complex than simply saying that each atom is a dipole, which makes the whole magnet a dipole, and when opposite poles are near one another, there is attraction (and vice versa). To sum up: is this explanation correct? And is this explanation really more simple? Pkeck 21:11, 17 Feb 2005 (UTC)
Fully agree a new Section on "Explaining Magnetic Attraction" is needed. For instance I came to this article to understand why a)iron is atracted by a magnet and b) why a magnet is attracted by another magnet, and I came empty handed (unless I missed it) Manuel
I'd want to know, in these permanent magnets, is the magnetic field constant, or will it drain when used? And if so, will it regenerate? Take the average ABC hanging on your fridge. Will they come down due to weakened magnetic properties? Naturally one would assume that eventually they should come down, due to energy transformation. But I have yet to see a magnet fall down/stop beeing magnetic. So basically, is there any info on energy in permanent magnets?
Do iron filings actually show the lines of magnetic force of a magnet, or do they just show how iron filings line up when they disturb the magnetic field of a magnet? -- Light current 10:26, 21 September 2005 (UTC)
Post copied from magnetic field
But the average permeability in the plane of the paper has been increased cf that of air. So this will distort the field?-- Light current 14:52, 21 September 2005 (UTC)
We're here to explain things, not to ascribe mystical qualities to phenomena!-- Light current 23:45, 12 July 2006 (UTC)
What's the point of having the units of force in the introduction? The attraction or repulsion is already indicated, and the units are irrelevant. Salsb 12:56, 21 September 2005 (UTC)
Deleting and clarifying the comparison of Gaussian-CGS to SI-MKS units. SI is not replacing the "older" CGS units. Maybe in some fields, but in physics we (almost) never use SI for electrodynamics. Also, mechanical CGS is primary in chemistry.
SamuelRiv
20:02, 14 October 2007 (UTC)
I think there must be a difference in practice and terminology between the US and Europe (maybe the rest of the world). CGS units are never used here in the UK - I last used them back in the 1960s when at school. Since then everything has been exclusively SI (MKS at first, as the SI system developed). The scientific community universally uses SI, and the use of other units should be deprecated.
I have noticed that authors from the US consistently make what appears from our perspective to be an error of terminology concerning B, H and the word 'field'. 'Field' can refer to a region of magnetised space (in this context), but as a physical quantity it is exclusively reserved for the quantity symbolised by H and measured in units of A/m. B, referred to in your units paragraph as 'the true field' is the symbol used for flux density, measured in Teslas. It is important to distinguish correctly between B and H , field and flux density, so the perpetuation of confusing (and confused) terminology is unfortunate. Can this be corrected please ? Andrew Smith —Preceding unsigned comment added by 82.32.50.77 ( talk) 17:20, 28 June 2009 (UTC)
between two magnet. it is not clear what μ ("mu") means, in the formula, and how to calculate this. if anyone can explain, and expand this subject. that would be great. thanks.
You guys need a history section. There is no mention of magnets and their history on WP. hmmm.-- Zereshk 09:58, 23 October 2005 (UTC)
So guys, how do they make magnets? Im assuming he's interested in the garden variety, solid stick things to your fridge variety. Thanks for any simple explainations..
A simple version you could try: a big magnet it made up of tiny particles, and when aligned in the same direction, they form a magnet-you can do a demonstration with small bits of paper. have N and S on each end and show how they become aligned form scrambled. Ursper 20:13, 29 April 2007 (UTC)
The bit that says
is incorrect. An electromagnetic wave will usually decrease by inverse square. So will the magnetic field of an isolated current element. An ordinary 'bar magnet', however, is usually modelled as a 'dipole element' in the far field (distances large compared with the separation of the poles). It becomes equivalent to an 'elemental current loop' whose far field is known to decrease with 1/ x³ -
RAClarke 20:33, 9 January 2006 (UTC)
Has anybody checked this "law" against a really reliable source like J. D. Jackson : " Classical Electrodynamics " , 3rd ed., (John Wiley & Sons, New York, 1998). I mean, I have studied physics now for quite a while and I never came across such a law.-- LN2 02:43, 18 February 2006 (UTC)
I Love Magnets
LN2: With the units given it is definitely wrong. The general form is OK, and it could be made correct depending on how you quantitatively define "magnetic pole. For an alternate form of the law see
http://geophysics.ou.edu/solid_earth/notes/mag_basic/mag_basic.html
which seems to work out correctly.
In the form given, the numerator is Weber^2 = Tesla^2 x m^4. The denominator is (Tesla X m/Amp) X (m^2), so the result is Tesla x Amp x meter. Since a Tesla is a Volt-second, the result is Volt x Amp x second x meter = Watt x second x meter = Joule x meter which is definitely not a correct unit for force.
If no one disputes this I'm going to edit the main article in a week or so, to the form given in the link.
hfoltz, 18 March 2006
Heron: I agree on the units of pole strength: A-m. That agrees with engineering texts such as Kraus. The geophysics.ou.edu website is interesting, from the format it's clear that the two pages were written by the same person. Again, I think it has to do with the unit system and either form could be correct. It's unfortunate that we've reached the 21st century and magnetic field units and terms still haven't been completely standardized. Hfoltz
Should we have a para on this here --- or not? -- Light current 23:32, 3 April 2006 (UTC)
I previously requested a source on this, as I had simply never heard of it before, and the wording "it is known" seemed to beg citation. DMacks did an excellent job of providing a timely response, however, now I have a new concern. The article Geomagnetic reversal states that the last occurance was approximately 780,000 years ago. However, as there are multiple different consensii on the age of the earth (see Dating creation), some of which hold that the planet is under 10,000 years old, I felt the simplest solution would be to simply change "it is known" to "it is believed". I think this wording will avoid any controversy between parties who hold the different viewpoints. Any thoughts? Dansiman 05:42, 14 April 2006 (UTC)
I suggest add a section that explains what would happen if we break a magnet into pieces Rockvee 05:31, 3 May 2006 (UTC)
I'd like to see a section on the history of magnets, I went to this article for that reason but there was no such section yet -- 213.118.83.229 08:53, 22 July 2006 (UTC)
Geographic North and South are the terms given to the points on the earth's surface through which the axis of the earths rotation pass, ie points at 90 degrees lattitude, points furthest from the equator, the "top" and "bottom" of the world. The magnatic poles are some distance from these and drift about somewhat. Navigators have to correct for this, particularly when near the poles. The section on geographic vs magnetic poles that points out (rightly) that the north (magnetic) pole is actually a south pole uses the term "geographic pole" in a way different to this. A way I've never come across before-- Mongreilf 20:24, 24 August 2006 (UTC)
Hello,
This is an invitation to discuss the merits of the inclusion of links to content provided by commercial entities in the 'Online References' section of this article on magnets. The following links have been or are currently present in this article:
http://www.arnoldmagnetics.com/mtc/index.htm
http://www.magnetsales.com/Design/DesignG.htm
http://www.rare-earth-magnets.com/magnet_university/magnet_university.htm
http://oersted.com/magnetizing.PDF
http://www.wondermagnet.com/magfaq.html
Each of these sites is primarily a site intended to convey information about the products or services of a company. In addition to their commercial content, each site has presented some valuable information related to Magnetics generally contained in a separate section or page of their site. Should these sites be included in this article under the section 'Online References' or should they all be excluded? Thanks for your input. —The preceding
unsigned comment was added by
72.205.10.4 (
talk)
The following is a comment by Mwanner about this subject that I thought should be included here:
Based on all these comments, I think that commercial information sources can be included as long as they are useful sources of information and not obviously promoting the products or services of the company. Once the external link is included an effort should be made to incorporate the useful content into the article and just reference the source. I started to incorporate some of the content into the article and invite anyone else to assist. The links are now in the External Links section of the article.
![]() | This article's factual accuracy is
disputed. (March 2008) |
A formula to give an approximate value of the force between magnets would very useful, and is often asked for in discussion groups. The one given here does seem to have errors when you try putting in practical values for L, R, x. The force, I think, cannot exceed 2*B^2*A/u0 (at very small x), where B is the flux density of each magnet, but the formula has no such limit. The results did not agree with a finite element simulation using FEMM (often the disagreement was orders of magnitude). It's a pity because a working approximate formula would be invaluable for practical engineering, and I haven't been able to find another one on the net. -- Gbeat 15:08, 26 December 2006 (UTC)
I'm working on a science fair project and need to learn if extreme temperatures would affect the strength of a magnet. What can you tell me regarding this question and what resources would you suggest I use to find out more?
Thanks for your help.
Walker Vaughn 69.255.10.35 17:28, 27 January 2007 (UTC)
Hey man, I'm doing the same project. SWEET. Sorry though, I can't help.
Can anyone explain how Magnets in computer software work and if they are malicious? 89.243.2.232 18:59, 2 February 2007 (UTC)Chris mcCletchie
please explain me about the field direction for the eleptical and round magnets.i found that for elipse the direction is opposite (having two directional flow of fields from same point)[PROOF:try such magnet to show its north south direction just by rotating not reversing it shows opposite direction] were as in bar magnet its from north to south all around.-- 59.145.240.133 ( talk) 05:39, 12 August 2008 (UTC)
Explain are permanent magnets really permanent Hey, props to whoever got the pic at the top of the article. —The preceding unsigned comment was added by 68.50.24.4 ( talk) 01:15, 22 February 2007 (UTC).
The two pictures are great, however, their relative left-right orientation seems reversed to me. By convention, the magnetic field lines of a permanent magnet loop from the North pole towards the South pole. It would be nice for the sake of symmetry, to have the pictures oriented in the same way, e.g. rotating the bottom picture of the solenoid by 180o Andonee ( talk) 02:32, 3 August 2009 (UTC)Andonee
![]() | It is requested that a physics diagram or diagrams be
included in this article to
improve its quality. Specific illustrations, plots or diagrams can be requested at the
Graphic Lab. For more information, refer to discussion on this page and/or the listing at Wikipedia:Requested images. |
It would be useful to illustrate:
-- Beland 04:01, 1 April 2007 (UTC)
What is non acctractio It was in a magnet website and if it is real then someone should add what it is. ( Ponser 20:12, 7 May 2007 (UTC))
It should not be the first section in the article (besides the intro), and it should not be an FAQ.
See WP:NOT#info. atomicthumbs 04:16, 8 June 2007 (UTC)
I rewrote the 'magnetic forces' section to make it a little more fun to read. I'd like my facts to be checked - they were mostly borrowed from the main articles specified and some of my own knowledge. Also, looking for consensus to remove the tag for expansion.
-- OEP 21:26, 25 June 2007 (UTC)
In the Idiot article I reverted a vandalism by user Nal101 that said: "In the real world, Jeff Cutuli and Jeff Snyder are considered idiots because they think that the Playstation 2 doesn't have magnets in the door."
The only other colaboration by this user is in this article, where he added this text: "Most notably, magnets have been used in virtually every piece of electronic equipment over the last 20 years, especially in devices that have rotational characteristics (I.E. cd/dvd player doors/trays). The magnet secures the door in place until it is de-magnetized (allowing the door/tray to open). Contrary to popular belief, magnets pose no harm to these devices."
Now, this doesn't look like vandalism at first glance, and since I don't know anything on the subject, I will just add a "citation needed". But please, someone could check this out? -- PeterCantropus 23:26, 29 July 2007 (UTC)
DMacks 15:00, 30 July 2007 (UTC)
The articles says magnetic moment is inversely proportional to the cube of distance. However in the same paragraph it gives a formula for magnetic moment as A·m². Dimensional analysis on this formula indicates magnetic moment is inversely propotional to the squre of distance. I realize from reading above that both statemens may be true, at different scales. If this is the case there needs to be a qualifier so that that there is no contradiction. I am fascinated by why the inverse square law is not applicable for the first statement and would love to undestand this better - so fleshing it out wood be great
Rmaytham 12:22, 15 September 2007 (UTC)
If I've got a magnet, how do I determine the north pole & the south pole of it? I guess a compass would be one way, but is there another way? -Joshua Hrouda
Joshua, Yes, the section of the article called: "North-south pole designation and the Earth's magnetic field" explains how to suspend a magnet so its North pole points North. Was that clear? John 19:05, 24 October 2007 (UTC)
I've heard that a Hall effect sensor can sense whether a N field or S field is near it, and give an output accordingly. If so, then how is it done? -Joshua Hrouda
Yes, the hall effect sensor is a small chip in a probe, and you just hold the probe near the pole of the magnet and read its polarity and strength off the meter. John 19:07, 24 October 2007 (UTC)
-Why when I broke a stick magnet that i had, did one side reverse polarity?
To illustrate this effect:
+ ======= -
+ ==== - \break\ - ==== +
^ where the magnet fits together, the ends repel each other.
This is counter-intuitive because it implies that one and only one side of the magnet switched polarity.
i experimented more and the same thing happened over and over again.
i did not figure out if the larger or smaller side switched, so that information is currently unknown to me.
WHY DOES THIS HAPPEN? what is magnetism?
- BriEnBest ( talk) 12:03, 22 November 2007 (UTC)
oh and btw how do i get rid of the dotted outlines?
BriEnBest (
talk)
12:04, 22 November 2007 (UTC)
The article states that graphite is diamagnetic, but one can observe an attraction between a piece of pencil lead and a neodymium magnet. If it was diamagnetic, wouldn't that mean it would be repelled? Or could this be due to ferromagnetic contamination in the graphite?-- 207.233.88.250 ( talk) 05:02, 7 December 2007 (UTC)
who made magnets and where was he born —Preceding unsigned comment added by 168.11.16.2 ( talk) 19:08, 12 February 2008 (UTC)
To show the relationshp between iorn magnet do the followinbg expiriment. You will need the following : a white sheet of computer paper iorn (2 hand fulls) north and south pole magnet 1:cover themagnet with computer paper 2:sprinkle on the iorn 3:slide paper back and forth When you see curved lines spreading diffrent ways those are the magnetic field lines —Preceding unsigned comment added by 207.203.80.27 ( talk) 17:44, 8 March 2008 (UTC)
what is a magnet use for —Preceding unsigned comment added by 209.94.220.183 ( talk) 08:55, 14 April 2008 (UTC)
I consider interesting people in physics write an article about Quantum Magnets, and at the bottom of this article could be found a link redirecting to the Quantum Magnet article. —Preceding unsigned comment added by 79.145.78.9 ( talk) 03:35, 3 May 2008 (UTC)
The pull is strongest near the poles. The closer to the pole, the stronger the pull. John ( talk) 05:17, 27 September 2008 (UTC)
“ | The force between two magnetic poles is given by:
where
The pole description is useful to practicing magneticians who design real-world magnets, but real magnets have a pole distribution more complex than a single north and south. Therefore, implementation of the pole idea is not simple. In some cases, one of the more complex formulae given below will be more useful. |
” |
By just looking at the units, I see something wrong immediately.
For example, it's obvious that the left hand side of the equation is supposed to be in units of force. The right hand side of the equation doesn't match up however. Look what happens when the dimensions are compared.
See the problem? (Hint: You don't think ohms is simply a subtraction of the charges' velocity do you?, and you don't think that because force * distance/time is power... that current is the square root of force, do you?, or that force^2 is the same as current?, or that voltage is velocity/force?) Here's another way to show what's definitely wrong with it.
According to Google ( http://www.google.com/search?q=1+weber+*+1+tesla), units of Teslas times units of Webers are supposed be in units of:
But if "m^2 kg^2 s^-4 A^-2" was the same as "A^2" then:
And since A*s is coulombs, then:
Looking back at the previous example, we had:
If you simple did the dimensions as made obvious in ohm's law, then:
It's soo wrong, yet check out what happens when you do the following:
So technically, the unknown dimension is supposed to be dimensions of electrical current times distance, yet the description says it is volt*seconds or webers. Are you telling me if you just take the current times distance and divide by time that you'll get voltage. Fine, I'll admit it makes intuitive sense:
However, if current * distance was webers (magnetic flux), when webers are actually in units of m kg s^-2 A^-1, then kg m s^-2 would be the same as A^2... the same problem we found earlier! Does twice the current really truly mean that the forces are going to be four times as great? Forces on WHAT?
If this is the correct formula, then I am genuinely shocked and dismayed (although may feel vastly superior to) than scientists, especially physicists today, even of those outside my own country (America), who can't see a blantant error (or shall we say, great discovery? =P), that someone who took one semester of University level physics and one semester of Cosmology (who majors in ACCOUNTING) can see due to the slightest bit of patience with what is generally supposed to be basic electromagnetic theory? Kmarinas86 (6sin8karma) 17:30, 10 August 2008 (UTC)
It makes no sense to keep the equations using the monopole concept if there are solutions given using the correct expressions. See Magnet#Force_between_two_cylindrical_magnets with a reference published and validated in 2009. Also see Magnetic_moment#Effects_of_an_external magnetic_field_on_a_magnetic_moment and the reference there for a discussion on why is not good to use the electrical analogy. -- User:Kakila , 17 February 2009 —Preceding undated comment added 08:56, 17 February 2010 (UTC).
Hi Wkipedia I'm one of your members. And I want to ask you if you can show me how magnet attracts metal in the page. I'll be waiting!!
Thanks —Preceding unsigned comment added by Anthony-2012 ( talk • contribs) 09:07, 21 September 2008 (UTC)
Alignment of magnetic domains. Kmarinas86 (6sin8karma) 10:55, 21 September 2008 (UTC)
There were two MKS systems, the rationalized and the un-rationalized. The SI system used the rationalized system. The un-rationalized system used U0=10-7. reference Dawes electrical engineering edition 4 page 221 —Preceding unsigned comment added by 203.47.38.170 ( talk) 05:41, 18 December 2008 (UTC)
hey people- im in the 6th grade and in the science fair anyone know how to make a magnet???? i am gonna try making a magnet then proving points of the north and south poles of it. any help???? —Preceding unsigned comment added by 76.112.80.95 ( talk) 23:28, 10 February 2009 (UTC)
Please is it possible to get magnet circular shape as big as 5ft wide and 8in thick. Meanwhile it must be very light cos I want if for a project which will be lifted up with balloons. However what should be the distant between two magnets if one will be at a point and the other will be on the other end pulling each other? I refer to the sized mention above. —Preceding unsigned comment added by Stuntprojects ( talk • contribs) 10:39, 24 April 2009 (UTC)
On these library computers, this page ( Magnet:article) experiences a print problem under firefox, but not internet explorer: Firefox prints a page with the citation header/footer, but nothing else. (Writing from the mall-library branch of Prescott Public library, Prescott, AZ, USA) 72.24.124.24 ( talk) 18:31, 28 April 2009 (UTC)
To me magnets describe objects that produce a noticeable magnetic field. Magnetism is about the phenomenon and the material. TStein ( talk) 06:27, 28 May 2009 (UTC)
I finally got a chance to move the material that I suggested. I also moved some material around as well. Please let me know, here, how it looks.
There is still a lot of stuff that needs to be done. I liked most of Chetvorno suggestions that I did not implement; I don't think I have the time to do them now, though. I also don't like the way the first 'physics of' section is structured; it has too much detail that is not needed for the rest of the article front loaded. If I had the time to figure out a better way to organize it I would. Unfortunately, there is just too much that needs doing in wikipedia physics articles in general that I only have enough time for the most egregious stuff. TStein ( talk) 21:21, 3 June 2009 (UTC)
I was about to design an electromagnet and, thinking I could simply jump on Wiki and get the info I needed, found no less than 21! articles on magnetism plus another 20! or so on related matters (there are more!). I'm good at research but jumping from link to link was doing my head in so I began a Summary on Magnetism. I have spent every waking hour of this week writing, researching, thinking and more thinking. I now have an intuitive feel for the subject but it was extremely difficult and quite confusing. I think there needs to be more consistency accross articles (units, symbols) whithout repitition, many more diagrams and a more intuitive structure. But especially, basic concepts should be thouroughly explained while keeping it brief, leaving out some of the more whimsicle topics (ie earths magnetic field) and putting others in an appendix (such as history, people). I guess ultimatly, one should be able to put ones research into practical use whthin hours, rather than weeks. What I would like to see is a complete overhaul of the entire subject of magnetism, and a summary article that ties the whole subject together (like my summary) for those who just want an intuitive and practical understanding whithout the hair loss. P.Taylor Q5101997 ( talk) 00:16, 1 November 2009 (UTC)
to stunt projects a magnet 5ft accross and 8 inches deep would weigh about 3tonnes. dont drop it on your foot, and dont go near it if you have had metal put in you for some medical reason —Preceding unsigned comment added by 123.211.94.229 ( talk) 04:09, 1 November 2009 (UTC)
I read somewhere that one could temporarily de-magnetize a permanent magnet by running a current through it.
Frustrated after finding nothing about it in a quick search, I tried some original research.
I touched a strong little horseshoe-shaped iron magnet to the poles of a 9-volt battery (magnet's poles were exactly the same distance apart as the battery's). Magnet latched on strongly, Got a spark, so plenty of current was going through the magnet. But magnet seemed about just as strong as when it attaches to the fridge. Maybe just a little weaker, not much.
If anyone has seen this as another means to de-mangnetize temporarily, please say so. —Preceding unsigned comment added by 66.167.61.90 ( talk) 02:09, 11 January 2010 (UTC)
I was reading the K&J Magnetics FAQ page which has a description of three use cases for which they provide measured holding forces. (1) The force to pull the magnet off a semi-infinite steel flat. (2) The force to separate two semi-infinite steel flats held together by the magnet. (3) The force to separate two identical magnets. Interestingly, their calculator (which is apparently based on emperical experiments, not theoretical results) indicates that case (2) is far and away the highest force.
To me, the most obvious question for those new to magnets is "how do I make them pull harder"? I've been scouring Wikipedia for a better understanding of this. Two interesting findings are the Halbach array found in refrigerator magnets and the magnetic base, which I'd always wondered about. With these things in mind, it seems like case 2 has the strongest holding force because the magnetic circuit formed with two pieces of steel has field lines that radiate out through the steel away from the magnet and through the air gap.
A few questions:
How does one get a useful intution for this stuff? Thanks. —Ben FrantzDale ( talk) 14:26, 12 January 2010 (UTC)
By dissolving a common magnet in hydrochloric acid, some of the metals it contains can be found out. I dissolved a common cheap magnet (the type they use in shower curtains) in HCl. The first color noticeable was the yellow color of iron chloride, formed by the reaction of the iron in the magnet with the hydrochloric acid. The next color noticeable was the red color of cobalt chloride, formed by the reaction of cobalt in the magnet with the hydrochloric acid.-- 98.221.179.18 ( talk) 21:23, 19 February 2010 (UTC)
what do you think about this [3] ? 147.91.12.157 ( talk) 19:56, 13 May 2010 (UTC)
How about a list of pop culture references to magnets? We could include bands such as Monster Magnet or popular you tube videos such as "Lobster Sticks to Magnet". I'm sure McGuyver has used a magnet before. I also feel that mentioning the inability of ICP members to understand how "fucking magnets" work would be an improvement for this article. 208.3.91.194 ( talk)
{{editsemiprotected}} please let me edit i promise i won't to vandalism please!!!!!!!!!!!!!!Pretty PLEASE!!!!!!!!!!!!!!!!!!........pleaseeeeeeeasssssee.
Bl52 ( talk) 09:06, 18 May 2010 (UTC)
Just to give all editors here a warning.
"I have forked out Calculating magnetic force section to force between magnets and will be hacking this section down soon."
If you have any objection to me doing this, or if you want to do it your self then please let me know here. This level of detail seems inappropriate to this general article. Plus it is used in other articles. Help finding other appropriate articles to link to force between magnets would be appreciated as well. TStein ( talk) 19:44, 10 August 2010 (UTC)
I think I noticed an incorrect equation
Where Mu_0 is the permeability of space (constant) and Mu is the permeability of a material
F = B^2*A/(2*Mu_0) is correct
H = B / Mu
Therefore:
F= H^2*A*Mu^2/(2*Mu_0)
If anyone can confirm this, can the equation be changed? Cocodave ( talk) 19:31, 7 September 2010 (UTC)
I see a lot of edits and tags placed on this page about citation needed et cetera. IF YOU DO NOT KNOW WHAT YOU ARE TALKING ABOUT DO NOT EDIT THIS ARTICLE You seem to be disputing and questioning the text solely because you don't understand the underlying principles of physics involved and/or maybe because you are on some wiki-cabal power trip.Unless you can point to a reference that is in contradiction to the universally accepted theories postulated in the article THEN DO NOT TAG OR EDIT THE ARTICLE. Try sticking to something you understand,like, Golf, or Camellia sinensis.
k thx bye 99.194.134.191 ( talk) 22:02, 2 January 2011 (UTC)
Ignoratio elenchi, dear sir
What you're doing is; (1)damaging the credibility of wikipedia (2)Inspiring qualified educated professionals to disassociate themselves from Wikipedia 1+2=3 or do you need a citation for this as well? (3)Wikipedia is not a definitive source for anything and has become the laughing stock of Colbert et al.
I need a reference that definitively shows how gravity works. Finding no such reference I make motion to delete the article gravity , clearly there is no such thing according to the rules here. 99.194.134.191 ( talk) 17:51, 3 January 2011 (UTC)
Sigh...look in current issue of JAMA, seriously guys just because YOU never heard of, YOU can't find a reference or YOU don't have access to professional journals... 99.194.155.166 ( talk) 14:46, 28 February 2011 (UTC)
Part of the purpose of citations is so that readers can go get more detailed information. RJFJR ( talk) 15:10, 28 February 2011 (UTC)
According to the article in JAMA Cellphone radiation caused a 7% increase in metabolic activity near the area of exposure, increased metabolic process equal, unquestionably, increased risk of cancers and tumors. Fucking magnets, how do they work? 99.194.155.204 ( talk) 15:43, 4 March 2011 (UTC)
![]() | This page is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
![]() | This page is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
According to the 14th citation in Magnetic dipole moment Boyer, Timothy H. (1988) The Force on a Magnetic Dipole. American Journal of Physics 56 (8): 688–692. doi:10.1119/1.15501. Using the electric dipole formula for the case where the magnetic field is rotational () is not correct. Two bar magnets do have a rotational field, hence the calculation given could be not correct. The webpage cited here http://instruct.tri-c.edu/fgram/web/Mdipole.htm uses the electric dipole approximation, which according to the paper is not correct. Aslo, looking at the formula given in Magnetic moment for th einteraction of two coils when separated a big distance, shows a dependecy while, the formula given here dependos on , where stands for the distance. I guess this difference comes form the shape effect of the bar manget, but it should be verified. In the webpage where the calculations are shown this is not explained. The formula is obtained directly from the electrical analogy. -- Kakila Monday, October 26 2009 —Preceding undated comment added 15:11, 26 October 2009 (UTC).
And my the force be with you. —Preceding unsigned comment added by 82.132.19.153 ( talk) 19:41, 14 April 2010 (UTC)
Would Wikipedia consider a listing for a speculative field such as Magnetic Motors?
See: http://www.pureenergysystems.com/os/MagneticMotors/
The article ( Magnet) says
And no, i'm not about to point out that the geomagnetic field repeatedly reverses.
It's an even more pedantic issue than that, but i think i recall that what gets labelled N by convention is a north-seeking pole rather than a north pole, from which it follows that the geomagnetic pole in the northern hemisphere is a south pole. Maybe my instructor got befuddled in trying to talk about red end of the compass needle not being a north pole, but the consequences of being wrong about this are so small that 90% of confident sources could be wrong and never realize it. Does someone have a super-reliable source on this? -- Jerzy 05:50, 2003 Dec 19 (UTC)
-- Pkeck 15:10, 2005 Jan 14 (EST)
This subject tends to be confusing.
Poles, North and South Magnetic
The North Pole of a magnet, or compass, is attracted toward the north geographic pole of the Earth. If you were to use a compass to determine polarity, the South Pole of the compass will point towards the North Pole of a magnet. The North Pole of a compass is more properly called the North Seeking Pole because it seeks out the geographical North Pole. Few people take the time to say “North Seeking” Pole. If you were to use a gauss meter, using an axial probe, the side of the magnet that gives you a positive reading will be the North Pole.
North Pole = North Seeking Pole = North Magnetic Pole = Positive Gauss Meter Reading
-- Mickmark21 ( talk) 10:45, 15 October 2010 (UTC)
I started to rework this page with the hopes of making it much clearer and more organized. I feel that magnets are one of those topics that the average person might be interested in, so the content here shouldn't be too in depth. If they want more information, that's what the links are there for. If anyone sees anything that isn't clear or feels that something is missing, please help out. -- Pkeck 11:21, 2004 Jan 14 (EST)
I'm curious about this new section. First (and most importantly), is this really an accurate way to describe what's going on in a magnet? I've never heard of or thought about it this way...which isn't to say that it's wrong, I've just never heard about it. Can you point to a page with more explanation of this idea of net current flowing around the surface of the magnet? I understand exactly what you mean, I just haven't ever heard of it.
Second, is it really easier to understand why magnets attract or repel one another through this explanation? I'm thinking that if you told the average person to imagine a cylinder of current carrying loops that all had current flowing perpendicular to the long axis of the cylinder and all in the same direction...and then to imagine how the current of adjacent loops negates the flow of current in their neighbors because they are flowing in opposite directions at adjacent points...which means that there will only be a net flow around the surface of the cylinder...I'm thinking the average person would be completely lost.
To be honest, it seems much more complex than simply saying that each atom is a dipole, which makes the whole magnet a dipole, and when opposite poles are near one another, there is attraction (and vice versa). To sum up: is this explanation correct? And is this explanation really more simple? Pkeck 21:11, 17 Feb 2005 (UTC)
Fully agree a new Section on "Explaining Magnetic Attraction" is needed. For instance I came to this article to understand why a)iron is atracted by a magnet and b) why a magnet is attracted by another magnet, and I came empty handed (unless I missed it) Manuel
I'd want to know, in these permanent magnets, is the magnetic field constant, or will it drain when used? And if so, will it regenerate? Take the average ABC hanging on your fridge. Will they come down due to weakened magnetic properties? Naturally one would assume that eventually they should come down, due to energy transformation. But I have yet to see a magnet fall down/stop beeing magnetic. So basically, is there any info on energy in permanent magnets?
Do iron filings actually show the lines of magnetic force of a magnet, or do they just show how iron filings line up when they disturb the magnetic field of a magnet? -- Light current 10:26, 21 September 2005 (UTC)
Post copied from magnetic field
But the average permeability in the plane of the paper has been increased cf that of air. So this will distort the field?-- Light current 14:52, 21 September 2005 (UTC)
We're here to explain things, not to ascribe mystical qualities to phenomena!-- Light current 23:45, 12 July 2006 (UTC)
What's the point of having the units of force in the introduction? The attraction or repulsion is already indicated, and the units are irrelevant. Salsb 12:56, 21 September 2005 (UTC)
Deleting and clarifying the comparison of Gaussian-CGS to SI-MKS units. SI is not replacing the "older" CGS units. Maybe in some fields, but in physics we (almost) never use SI for electrodynamics. Also, mechanical CGS is primary in chemistry.
SamuelRiv
20:02, 14 October 2007 (UTC)
I think there must be a difference in practice and terminology between the US and Europe (maybe the rest of the world). CGS units are never used here in the UK - I last used them back in the 1960s when at school. Since then everything has been exclusively SI (MKS at first, as the SI system developed). The scientific community universally uses SI, and the use of other units should be deprecated.
I have noticed that authors from the US consistently make what appears from our perspective to be an error of terminology concerning B, H and the word 'field'. 'Field' can refer to a region of magnetised space (in this context), but as a physical quantity it is exclusively reserved for the quantity symbolised by H and measured in units of A/m. B, referred to in your units paragraph as 'the true field' is the symbol used for flux density, measured in Teslas. It is important to distinguish correctly between B and H , field and flux density, so the perpetuation of confusing (and confused) terminology is unfortunate. Can this be corrected please ? Andrew Smith —Preceding unsigned comment added by 82.32.50.77 ( talk) 17:20, 28 June 2009 (UTC)
between two magnet. it is not clear what μ ("mu") means, in the formula, and how to calculate this. if anyone can explain, and expand this subject. that would be great. thanks.
You guys need a history section. There is no mention of magnets and their history on WP. hmmm.-- Zereshk 09:58, 23 October 2005 (UTC)
So guys, how do they make magnets? Im assuming he's interested in the garden variety, solid stick things to your fridge variety. Thanks for any simple explainations..
A simple version you could try: a big magnet it made up of tiny particles, and when aligned in the same direction, they form a magnet-you can do a demonstration with small bits of paper. have N and S on each end and show how they become aligned form scrambled. Ursper 20:13, 29 April 2007 (UTC)
The bit that says
is incorrect. An electromagnetic wave will usually decrease by inverse square. So will the magnetic field of an isolated current element. An ordinary 'bar magnet', however, is usually modelled as a 'dipole element' in the far field (distances large compared with the separation of the poles). It becomes equivalent to an 'elemental current loop' whose far field is known to decrease with 1/ x³ -
RAClarke 20:33, 9 January 2006 (UTC)
Has anybody checked this "law" against a really reliable source like J. D. Jackson : " Classical Electrodynamics " , 3rd ed., (John Wiley & Sons, New York, 1998). I mean, I have studied physics now for quite a while and I never came across such a law.-- LN2 02:43, 18 February 2006 (UTC)
I Love Magnets
LN2: With the units given it is definitely wrong. The general form is OK, and it could be made correct depending on how you quantitatively define "magnetic pole. For an alternate form of the law see
http://geophysics.ou.edu/solid_earth/notes/mag_basic/mag_basic.html
which seems to work out correctly.
In the form given, the numerator is Weber^2 = Tesla^2 x m^4. The denominator is (Tesla X m/Amp) X (m^2), so the result is Tesla x Amp x meter. Since a Tesla is a Volt-second, the result is Volt x Amp x second x meter = Watt x second x meter = Joule x meter which is definitely not a correct unit for force.
If no one disputes this I'm going to edit the main article in a week or so, to the form given in the link.
hfoltz, 18 March 2006
Heron: I agree on the units of pole strength: A-m. That agrees with engineering texts such as Kraus. The geophysics.ou.edu website is interesting, from the format it's clear that the two pages were written by the same person. Again, I think it has to do with the unit system and either form could be correct. It's unfortunate that we've reached the 21st century and magnetic field units and terms still haven't been completely standardized. Hfoltz
Should we have a para on this here --- or not? -- Light current 23:32, 3 April 2006 (UTC)
I previously requested a source on this, as I had simply never heard of it before, and the wording "it is known" seemed to beg citation. DMacks did an excellent job of providing a timely response, however, now I have a new concern. The article Geomagnetic reversal states that the last occurance was approximately 780,000 years ago. However, as there are multiple different consensii on the age of the earth (see Dating creation), some of which hold that the planet is under 10,000 years old, I felt the simplest solution would be to simply change "it is known" to "it is believed". I think this wording will avoid any controversy between parties who hold the different viewpoints. Any thoughts? Dansiman 05:42, 14 April 2006 (UTC)
I suggest add a section that explains what would happen if we break a magnet into pieces Rockvee 05:31, 3 May 2006 (UTC)
I'd like to see a section on the history of magnets, I went to this article for that reason but there was no such section yet -- 213.118.83.229 08:53, 22 July 2006 (UTC)
Geographic North and South are the terms given to the points on the earth's surface through which the axis of the earths rotation pass, ie points at 90 degrees lattitude, points furthest from the equator, the "top" and "bottom" of the world. The magnatic poles are some distance from these and drift about somewhat. Navigators have to correct for this, particularly when near the poles. The section on geographic vs magnetic poles that points out (rightly) that the north (magnetic) pole is actually a south pole uses the term "geographic pole" in a way different to this. A way I've never come across before-- Mongreilf 20:24, 24 August 2006 (UTC)
Hello,
This is an invitation to discuss the merits of the inclusion of links to content provided by commercial entities in the 'Online References' section of this article on magnets. The following links have been or are currently present in this article:
http://www.arnoldmagnetics.com/mtc/index.htm
http://www.magnetsales.com/Design/DesignG.htm
http://www.rare-earth-magnets.com/magnet_university/magnet_university.htm
http://oersted.com/magnetizing.PDF
http://www.wondermagnet.com/magfaq.html
Each of these sites is primarily a site intended to convey information about the products or services of a company. In addition to their commercial content, each site has presented some valuable information related to Magnetics generally contained in a separate section or page of their site. Should these sites be included in this article under the section 'Online References' or should they all be excluded? Thanks for your input. —The preceding
unsigned comment was added by
72.205.10.4 (
talk)
The following is a comment by Mwanner about this subject that I thought should be included here:
Based on all these comments, I think that commercial information sources can be included as long as they are useful sources of information and not obviously promoting the products or services of the company. Once the external link is included an effort should be made to incorporate the useful content into the article and just reference the source. I started to incorporate some of the content into the article and invite anyone else to assist. The links are now in the External Links section of the article.
![]() | This article's factual accuracy is
disputed. (March 2008) |
A formula to give an approximate value of the force between magnets would very useful, and is often asked for in discussion groups. The one given here does seem to have errors when you try putting in practical values for L, R, x. The force, I think, cannot exceed 2*B^2*A/u0 (at very small x), where B is the flux density of each magnet, but the formula has no such limit. The results did not agree with a finite element simulation using FEMM (often the disagreement was orders of magnitude). It's a pity because a working approximate formula would be invaluable for practical engineering, and I haven't been able to find another one on the net. -- Gbeat 15:08, 26 December 2006 (UTC)
I'm working on a science fair project and need to learn if extreme temperatures would affect the strength of a magnet. What can you tell me regarding this question and what resources would you suggest I use to find out more?
Thanks for your help.
Walker Vaughn 69.255.10.35 17:28, 27 January 2007 (UTC)
Hey man, I'm doing the same project. SWEET. Sorry though, I can't help.
Can anyone explain how Magnets in computer software work and if they are malicious? 89.243.2.232 18:59, 2 February 2007 (UTC)Chris mcCletchie
please explain me about the field direction for the eleptical and round magnets.i found that for elipse the direction is opposite (having two directional flow of fields from same point)[PROOF:try such magnet to show its north south direction just by rotating not reversing it shows opposite direction] were as in bar magnet its from north to south all around.-- 59.145.240.133 ( talk) 05:39, 12 August 2008 (UTC)
Explain are permanent magnets really permanent Hey, props to whoever got the pic at the top of the article. —The preceding unsigned comment was added by 68.50.24.4 ( talk) 01:15, 22 February 2007 (UTC).
The two pictures are great, however, their relative left-right orientation seems reversed to me. By convention, the magnetic field lines of a permanent magnet loop from the North pole towards the South pole. It would be nice for the sake of symmetry, to have the pictures oriented in the same way, e.g. rotating the bottom picture of the solenoid by 180o Andonee ( talk) 02:32, 3 August 2009 (UTC)Andonee
![]() | It is requested that a physics diagram or diagrams be
included in this article to
improve its quality. Specific illustrations, plots or diagrams can be requested at the
Graphic Lab. For more information, refer to discussion on this page and/or the listing at Wikipedia:Requested images. |
It would be useful to illustrate:
-- Beland 04:01, 1 April 2007 (UTC)
What is non acctractio It was in a magnet website and if it is real then someone should add what it is. ( Ponser 20:12, 7 May 2007 (UTC))
It should not be the first section in the article (besides the intro), and it should not be an FAQ.
See WP:NOT#info. atomicthumbs 04:16, 8 June 2007 (UTC)
I rewrote the 'magnetic forces' section to make it a little more fun to read. I'd like my facts to be checked - they were mostly borrowed from the main articles specified and some of my own knowledge. Also, looking for consensus to remove the tag for expansion.
-- OEP 21:26, 25 June 2007 (UTC)
In the Idiot article I reverted a vandalism by user Nal101 that said: "In the real world, Jeff Cutuli and Jeff Snyder are considered idiots because they think that the Playstation 2 doesn't have magnets in the door."
The only other colaboration by this user is in this article, where he added this text: "Most notably, magnets have been used in virtually every piece of electronic equipment over the last 20 years, especially in devices that have rotational characteristics (I.E. cd/dvd player doors/trays). The magnet secures the door in place until it is de-magnetized (allowing the door/tray to open). Contrary to popular belief, magnets pose no harm to these devices."
Now, this doesn't look like vandalism at first glance, and since I don't know anything on the subject, I will just add a "citation needed". But please, someone could check this out? -- PeterCantropus 23:26, 29 July 2007 (UTC)
DMacks 15:00, 30 July 2007 (UTC)
The articles says magnetic moment is inversely proportional to the cube of distance. However in the same paragraph it gives a formula for magnetic moment as A·m². Dimensional analysis on this formula indicates magnetic moment is inversely propotional to the squre of distance. I realize from reading above that both statemens may be true, at different scales. If this is the case there needs to be a qualifier so that that there is no contradiction. I am fascinated by why the inverse square law is not applicable for the first statement and would love to undestand this better - so fleshing it out wood be great
Rmaytham 12:22, 15 September 2007 (UTC)
If I've got a magnet, how do I determine the north pole & the south pole of it? I guess a compass would be one way, but is there another way? -Joshua Hrouda
Joshua, Yes, the section of the article called: "North-south pole designation and the Earth's magnetic field" explains how to suspend a magnet so its North pole points North. Was that clear? John 19:05, 24 October 2007 (UTC)
I've heard that a Hall effect sensor can sense whether a N field or S field is near it, and give an output accordingly. If so, then how is it done? -Joshua Hrouda
Yes, the hall effect sensor is a small chip in a probe, and you just hold the probe near the pole of the magnet and read its polarity and strength off the meter. John 19:07, 24 October 2007 (UTC)
-Why when I broke a stick magnet that i had, did one side reverse polarity?
To illustrate this effect:
+ ======= -
+ ==== - \break\ - ==== +
^ where the magnet fits together, the ends repel each other.
This is counter-intuitive because it implies that one and only one side of the magnet switched polarity.
i experimented more and the same thing happened over and over again.
i did not figure out if the larger or smaller side switched, so that information is currently unknown to me.
WHY DOES THIS HAPPEN? what is magnetism?
- BriEnBest ( talk) 12:03, 22 November 2007 (UTC)
oh and btw how do i get rid of the dotted outlines?
BriEnBest (
talk)
12:04, 22 November 2007 (UTC)
The article states that graphite is diamagnetic, but one can observe an attraction between a piece of pencil lead and a neodymium magnet. If it was diamagnetic, wouldn't that mean it would be repelled? Or could this be due to ferromagnetic contamination in the graphite?-- 207.233.88.250 ( talk) 05:02, 7 December 2007 (UTC)
who made magnets and where was he born —Preceding unsigned comment added by 168.11.16.2 ( talk) 19:08, 12 February 2008 (UTC)
To show the relationshp between iorn magnet do the followinbg expiriment. You will need the following : a white sheet of computer paper iorn (2 hand fulls) north and south pole magnet 1:cover themagnet with computer paper 2:sprinkle on the iorn 3:slide paper back and forth When you see curved lines spreading diffrent ways those are the magnetic field lines —Preceding unsigned comment added by 207.203.80.27 ( talk) 17:44, 8 March 2008 (UTC)
what is a magnet use for —Preceding unsigned comment added by 209.94.220.183 ( talk) 08:55, 14 April 2008 (UTC)
I consider interesting people in physics write an article about Quantum Magnets, and at the bottom of this article could be found a link redirecting to the Quantum Magnet article. —Preceding unsigned comment added by 79.145.78.9 ( talk) 03:35, 3 May 2008 (UTC)
The pull is strongest near the poles. The closer to the pole, the stronger the pull. John ( talk) 05:17, 27 September 2008 (UTC)
“ | The force between two magnetic poles is given by:
where
The pole description is useful to practicing magneticians who design real-world magnets, but real magnets have a pole distribution more complex than a single north and south. Therefore, implementation of the pole idea is not simple. In some cases, one of the more complex formulae given below will be more useful. |
” |
By just looking at the units, I see something wrong immediately.
For example, it's obvious that the left hand side of the equation is supposed to be in units of force. The right hand side of the equation doesn't match up however. Look what happens when the dimensions are compared.
See the problem? (Hint: You don't think ohms is simply a subtraction of the charges' velocity do you?, and you don't think that because force * distance/time is power... that current is the square root of force, do you?, or that force^2 is the same as current?, or that voltage is velocity/force?) Here's another way to show what's definitely wrong with it.
According to Google ( http://www.google.com/search?q=1+weber+*+1+tesla), units of Teslas times units of Webers are supposed be in units of:
But if "m^2 kg^2 s^-4 A^-2" was the same as "A^2" then:
And since A*s is coulombs, then:
Looking back at the previous example, we had:
If you simple did the dimensions as made obvious in ohm's law, then:
It's soo wrong, yet check out what happens when you do the following:
So technically, the unknown dimension is supposed to be dimensions of electrical current times distance, yet the description says it is volt*seconds or webers. Are you telling me if you just take the current times distance and divide by time that you'll get voltage. Fine, I'll admit it makes intuitive sense:
However, if current * distance was webers (magnetic flux), when webers are actually in units of m kg s^-2 A^-1, then kg m s^-2 would be the same as A^2... the same problem we found earlier! Does twice the current really truly mean that the forces are going to be four times as great? Forces on WHAT?
If this is the correct formula, then I am genuinely shocked and dismayed (although may feel vastly superior to) than scientists, especially physicists today, even of those outside my own country (America), who can't see a blantant error (or shall we say, great discovery? =P), that someone who took one semester of University level physics and one semester of Cosmology (who majors in ACCOUNTING) can see due to the slightest bit of patience with what is generally supposed to be basic electromagnetic theory? Kmarinas86 (6sin8karma) 17:30, 10 August 2008 (UTC)
It makes no sense to keep the equations using the monopole concept if there are solutions given using the correct expressions. See Magnet#Force_between_two_cylindrical_magnets with a reference published and validated in 2009. Also see Magnetic_moment#Effects_of_an_external magnetic_field_on_a_magnetic_moment and the reference there for a discussion on why is not good to use the electrical analogy. -- User:Kakila , 17 February 2009 —Preceding undated comment added 08:56, 17 February 2010 (UTC).
Hi Wkipedia I'm one of your members. And I want to ask you if you can show me how magnet attracts metal in the page. I'll be waiting!!
Thanks —Preceding unsigned comment added by Anthony-2012 ( talk • contribs) 09:07, 21 September 2008 (UTC)
Alignment of magnetic domains. Kmarinas86 (6sin8karma) 10:55, 21 September 2008 (UTC)
There were two MKS systems, the rationalized and the un-rationalized. The SI system used the rationalized system. The un-rationalized system used U0=10-7. reference Dawes electrical engineering edition 4 page 221 —Preceding unsigned comment added by 203.47.38.170 ( talk) 05:41, 18 December 2008 (UTC)
hey people- im in the 6th grade and in the science fair anyone know how to make a magnet???? i am gonna try making a magnet then proving points of the north and south poles of it. any help???? —Preceding unsigned comment added by 76.112.80.95 ( talk) 23:28, 10 February 2009 (UTC)
Please is it possible to get magnet circular shape as big as 5ft wide and 8in thick. Meanwhile it must be very light cos I want if for a project which will be lifted up with balloons. However what should be the distant between two magnets if one will be at a point and the other will be on the other end pulling each other? I refer to the sized mention above. —Preceding unsigned comment added by Stuntprojects ( talk • contribs) 10:39, 24 April 2009 (UTC)
On these library computers, this page ( Magnet:article) experiences a print problem under firefox, but not internet explorer: Firefox prints a page with the citation header/footer, but nothing else. (Writing from the mall-library branch of Prescott Public library, Prescott, AZ, USA) 72.24.124.24 ( talk) 18:31, 28 April 2009 (UTC)
To me magnets describe objects that produce a noticeable magnetic field. Magnetism is about the phenomenon and the material. TStein ( talk) 06:27, 28 May 2009 (UTC)
I finally got a chance to move the material that I suggested. I also moved some material around as well. Please let me know, here, how it looks.
There is still a lot of stuff that needs to be done. I liked most of Chetvorno suggestions that I did not implement; I don't think I have the time to do them now, though. I also don't like the way the first 'physics of' section is structured; it has too much detail that is not needed for the rest of the article front loaded. If I had the time to figure out a better way to organize it I would. Unfortunately, there is just too much that needs doing in wikipedia physics articles in general that I only have enough time for the most egregious stuff. TStein ( talk) 21:21, 3 June 2009 (UTC)
I was about to design an electromagnet and, thinking I could simply jump on Wiki and get the info I needed, found no less than 21! articles on magnetism plus another 20! or so on related matters (there are more!). I'm good at research but jumping from link to link was doing my head in so I began a Summary on Magnetism. I have spent every waking hour of this week writing, researching, thinking and more thinking. I now have an intuitive feel for the subject but it was extremely difficult and quite confusing. I think there needs to be more consistency accross articles (units, symbols) whithout repitition, many more diagrams and a more intuitive structure. But especially, basic concepts should be thouroughly explained while keeping it brief, leaving out some of the more whimsicle topics (ie earths magnetic field) and putting others in an appendix (such as history, people). I guess ultimatly, one should be able to put ones research into practical use whthin hours, rather than weeks. What I would like to see is a complete overhaul of the entire subject of magnetism, and a summary article that ties the whole subject together (like my summary) for those who just want an intuitive and practical understanding whithout the hair loss. P.Taylor Q5101997 ( talk) 00:16, 1 November 2009 (UTC)
to stunt projects a magnet 5ft accross and 8 inches deep would weigh about 3tonnes. dont drop it on your foot, and dont go near it if you have had metal put in you for some medical reason —Preceding unsigned comment added by 123.211.94.229 ( talk) 04:09, 1 November 2009 (UTC)
I read somewhere that one could temporarily de-magnetize a permanent magnet by running a current through it.
Frustrated after finding nothing about it in a quick search, I tried some original research.
I touched a strong little horseshoe-shaped iron magnet to the poles of a 9-volt battery (magnet's poles were exactly the same distance apart as the battery's). Magnet latched on strongly, Got a spark, so plenty of current was going through the magnet. But magnet seemed about just as strong as when it attaches to the fridge. Maybe just a little weaker, not much.
If anyone has seen this as another means to de-mangnetize temporarily, please say so. —Preceding unsigned comment added by 66.167.61.90 ( talk) 02:09, 11 January 2010 (UTC)
I was reading the K&J Magnetics FAQ page which has a description of three use cases for which they provide measured holding forces. (1) The force to pull the magnet off a semi-infinite steel flat. (2) The force to separate two semi-infinite steel flats held together by the magnet. (3) The force to separate two identical magnets. Interestingly, their calculator (which is apparently based on emperical experiments, not theoretical results) indicates that case (2) is far and away the highest force.
To me, the most obvious question for those new to magnets is "how do I make them pull harder"? I've been scouring Wikipedia for a better understanding of this. Two interesting findings are the Halbach array found in refrigerator magnets and the magnetic base, which I'd always wondered about. With these things in mind, it seems like case 2 has the strongest holding force because the magnetic circuit formed with two pieces of steel has field lines that radiate out through the steel away from the magnet and through the air gap.
A few questions:
How does one get a useful intution for this stuff? Thanks. —Ben FrantzDale ( talk) 14:26, 12 January 2010 (UTC)
By dissolving a common magnet in hydrochloric acid, some of the metals it contains can be found out. I dissolved a common cheap magnet (the type they use in shower curtains) in HCl. The first color noticeable was the yellow color of iron chloride, formed by the reaction of the iron in the magnet with the hydrochloric acid. The next color noticeable was the red color of cobalt chloride, formed by the reaction of cobalt in the magnet with the hydrochloric acid.-- 98.221.179.18 ( talk) 21:23, 19 February 2010 (UTC)
what do you think about this [3] ? 147.91.12.157 ( talk) 19:56, 13 May 2010 (UTC)
How about a list of pop culture references to magnets? We could include bands such as Monster Magnet or popular you tube videos such as "Lobster Sticks to Magnet". I'm sure McGuyver has used a magnet before. I also feel that mentioning the inability of ICP members to understand how "fucking magnets" work would be an improvement for this article. 208.3.91.194 ( talk)
{{editsemiprotected}} please let me edit i promise i won't to vandalism please!!!!!!!!!!!!!!Pretty PLEASE!!!!!!!!!!!!!!!!!!........pleaseeeeeeeasssssee.
Bl52 ( talk) 09:06, 18 May 2010 (UTC)
Just to give all editors here a warning.
"I have forked out Calculating magnetic force section to force between magnets and will be hacking this section down soon."
If you have any objection to me doing this, or if you want to do it your self then please let me know here. This level of detail seems inappropriate to this general article. Plus it is used in other articles. Help finding other appropriate articles to link to force between magnets would be appreciated as well. TStein ( talk) 19:44, 10 August 2010 (UTC)
I think I noticed an incorrect equation
Where Mu_0 is the permeability of space (constant) and Mu is the permeability of a material
F = B^2*A/(2*Mu_0) is correct
H = B / Mu
Therefore:
F= H^2*A*Mu^2/(2*Mu_0)
If anyone can confirm this, can the equation be changed? Cocodave ( talk) 19:31, 7 September 2010 (UTC)
I see a lot of edits and tags placed on this page about citation needed et cetera. IF YOU DO NOT KNOW WHAT YOU ARE TALKING ABOUT DO NOT EDIT THIS ARTICLE You seem to be disputing and questioning the text solely because you don't understand the underlying principles of physics involved and/or maybe because you are on some wiki-cabal power trip.Unless you can point to a reference that is in contradiction to the universally accepted theories postulated in the article THEN DO NOT TAG OR EDIT THE ARTICLE. Try sticking to something you understand,like, Golf, or Camellia sinensis.
k thx bye 99.194.134.191 ( talk) 22:02, 2 January 2011 (UTC)
Ignoratio elenchi, dear sir
What you're doing is; (1)damaging the credibility of wikipedia (2)Inspiring qualified educated professionals to disassociate themselves from Wikipedia 1+2=3 or do you need a citation for this as well? (3)Wikipedia is not a definitive source for anything and has become the laughing stock of Colbert et al.
I need a reference that definitively shows how gravity works. Finding no such reference I make motion to delete the article gravity , clearly there is no such thing according to the rules here. 99.194.134.191 ( talk) 17:51, 3 January 2011 (UTC)
Sigh...look in current issue of JAMA, seriously guys just because YOU never heard of, YOU can't find a reference or YOU don't have access to professional journals... 99.194.155.166 ( talk) 14:46, 28 February 2011 (UTC)
Part of the purpose of citations is so that readers can go get more detailed information. RJFJR ( talk) 15:10, 28 February 2011 (UTC)
According to the article in JAMA Cellphone radiation caused a 7% increase in metabolic activity near the area of exposure, increased metabolic process equal, unquestionably, increased risk of cancers and tumors. Fucking magnets, how do they work? 99.194.155.204 ( talk) 15:43, 4 March 2011 (UTC)
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