Science Forums Biology Forum Molecular Biology Forum Physics Chemistry Forum What is the meaning of the field about a conventional magnet?

 Physics Forum Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.

# What is the meaning of the field about a conventional magnet?

## What is the meaning of the field about a conventional magnet? - Physics Forum

### What is the meaning of the field about a conventional magnet? - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.

#1
08-07-2006, 08:20 PM
 Jeff Silverman (Remove the letters in all caps) Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

We take a conventional magnet, put a stiff card on top if, pour on some
iron filings and shake gently. The iron filings line up according to
the magnetic "lines of force". School children perform this experiment
and it always impresses the hell out of 'em because the phenomena is so
alien to their experience to this point. Furthermore, we can put a
small compass near a magnet and note which way it points and we get the
same result.

Then, in undergraduate physics classes, we learn that the
electromagnetic force is carried by photons. So far, so good. But what
is the motion or action of the photons that cause the force lines that
we observe?

I suppose that the same question could be asked about two electrical
charges in reasonable proximity but I'm not sure how to run that experiment.

Many thanks,

Jeff Silverman
#2
08-08-2006, 12:12 AM
 N:dlzc D:aol T:com \(dlzc\) Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

Dear Jeff Silverman:

"Jeff Silverman (Remove the letters in all caps)"
<[Only registered users see links. ]> wrote in message
news:44d7a07b\$0\$57733\$[Only registered users see links. ] ...

*virtual* photons.

It is the action of conveying electro*static* force (aka.
charge). Length contraction/time dilation provide the particular
geometries associated with magnetism.

Look for demonstrations involving pith balls on string.

David A. Smith

#3
08-08-2006, 06:30 PM
 PD Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

Jeff Silverman (Remove the letters in all caps) wrote:

An excellent question. It's excellent because it points to so many
notions that *sound* plausibly correct but are not. For example, one
might guess that the photons travel in paths that follow the lines of
force. They do not.

So what is going on, then? I'll try to put it in colloquial terms and
as a result will be a little sloppy. Don't make too much of what I say.

In an interaction between a magnet and an iron filing, *lots* of
photons are exchanged. These do a lot of things, but chiefly they cause
jiggling, small perturbations. When things get jiggled, they tend to
settle, and settling really means migrating to a position/orientiation
of lower energy.

What a photon from an orbiting atom does when it encounters an orbiting
electron in another (distant) atom is jiggle it so that the planes of
orientation of the electron orbits tend to line up -- this turns out to
be a position of lower energy. The lines of force tell you essentially
what is the orientiation of minimum energy, for every point in space
surrounding a magnet, and the density of the lines of force tell you
how steep the slope is to get to that orientation if the filing is not
in that orientation.

That's basically all there is to it, in a very very coarse fashion. Now
the quantitative details require more work...

PD

#4
08-09-2006, 06:59 AM
 Jeff Silverman (Remove the letters in all caps) Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

N:dlzc D:aol T:com (dlzc) wrote:

I think I know what a "virtual" electron or a "virtual" positron is: if
you have a photon rocketing through space, it may spontaneously form an
electron-positron pair, which will collapse on itself and convert back
to a photon. But what is a virtual photon?

I don't understand this answer. If the space/time in the region is
distorted, then why isn't light affected when it travels through the
vacinity of the magnet?

Oh. I supposed you could also do it with two Van De Graff generators.
Duh. Okay, that wasn't a very good question.

Jeff Silverman
#5
08-09-2006, 10:59 AM
 pom Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

Jeff Silverman (Remove the letters in all caps) a écrit :
Hello,
I really don't know why one has to speak of photons in relation with a
"static" magnetic field.
The famous duality between photons and waves is just that : you have to
have a wave. If the period of your wave tends to infinity, I wonder
about the strange "photon" you will get...
The inter action between a permanent magnet field and the "filings" is
in reality an interaction between a paramagnetic or ferromagnetic VERY
anisotropic particle with a static field
- very difficult to explain without solid state magnetics-
and therefore excludes in some way or the other when an explanation is
given to beginners.
An experiment with a electrostatic field :
In a flat glas container, put some very visquous transparent and
non-conducting fluid (castoroil will work fine), two electrodes of
convenient form and strew some not too finely ground flour over the
surface.
When applying a potential difference of several kV the particles will
align as in the magnetostatic case.
Good luck
pom
#6
08-09-2006, 01:11 PM
 N:dlzc D:aol T:com \(dlzc\) Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

Dear Jeff Silverman:

"Jeff Silverman (Remove the letters in all caps)"
<[Only registered users see links. ]> wrote in message
news:44D987B7.4050505@STOPSPAMNOW.commercialventva cQ.com...

That is simply "spontaneous pair creation" of real particles.

[Only registered users see links. ]
.... it is a particle that is exchanged between two charges. Many
physicists believe that there are no real photons, simply a very
long series of virtual photons (doing a baton pass).

Since this effect is correlated with "linear" motion, and not
mass, "gravitational lensing" is not an issue. And there are
predicted, very tiny effects on photons passing through very
powerful magnetic fields. Currently being tooled up to see if
the theory works (and I can't remember the name).

And see what effect a magnetic field has on a moving charged pith
ball...

David A. Smith

#7
08-09-2006, 06:15 PM
 pom Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

N:dlzc D:aol T:com (dlzc) a écrit :
Hmm...
are you sure you meant to reply to me, pom or M. Silverman?
Anyway, your message has only a very slight relation to the original one.
Baffled
POM
#8
08-10-2006, 12:18 AM
 N:dlzc D:aol T:com \(dlzc\) Guest Posts: n/a
What is the meaning of the field about a conventional magnet?

Dear pom:

"pom" <[Only registered users see links. ]> wrote in message
news:44da2629\$0\$13514\$[Only registered users see links. ].fr...
....

See where I said "Dear Jeff Silverman" above?

Blame it on Thunderbird...

David A. Smith

 Tags conventional , field , magnet , meaning

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home General Science Forums     Biology Forum     New Member Introductions Forum     Chemistry Forum         Organic Chemistry Forum     Physics Forum     General Science Questions and Layperson Board         Science and Religion Forum         Zoology Forum     Environmental Sciences and Issues General Forum     Chit Chat         Science and Lab Jokes     Article Discussion     Molecular Biology News and Announcements         Conferences , Symposiums and Meetings         Molecular Station Suggestion Forum         Instructions for Posting, Help, and Frequently Asked Questions     Science News and Views         Molecular Biology Lectures and Videos     Science Careers         Post-doctoral         Medical School         Ph.D Doctor of Philosophy         Science Jobs Forum Molecular Research Topics Forum     PCR - Polymerase Chain Reaction Forum         Real-Time PCR and Quantitative PCR Forum     Bioinformatics         BioStatistics Forum     Molecular Biology Techniques         Molecular Cloning Forum         Electrophoretic Mobility Shift Assay Forum         Agarose Gel Electrophoresis Forum         BioPhysics Forum         Gene Therapy     Cell Biology and Cell Culture         Apoptosis, Autophagy, and Necrosis Forum         Flow Cytometry Forum         Transfection Forum         Confocal - Microscopy Imaging Techniques         Immunology and Host-Pathogen Interactions         Signalling Biology         Stem Cell Forum     Basic Lab Protocols and Techniques         SDS-PAGE Gel Electrophoresis Forum     DNA Techniques         DNA Extraction Forum         cDNA Forum     Epigenetics Forum: DNA Methylation, Histone and Chromatin Study         ChIP Chromatin Immunoprecipitation Forum     Protein Science         Antibody Forum             Immunoprecipitation Forum         Western Blot Forum         Protein Crystallography Forum         Recombinant Protein Forum         ELISA Assay Forum         Protein Forum     Proteomics Forum         Peptide Forum         Mass Spectrometry Forum         2-D Gel Electrophoresis Forum     Omics and Genomics Forum         Microarrays Forum         Genomics Forum     RNA Techniques Forum         RNAi and SiRNA Forum     Histology Forum         Immunohistochemistry Forum         Immunocytochemistry Forum         Electron Microscopy Forum         Immunofluorescence Forum     Protocols and Methods Forum     Molecular Biology Articles and Protocols     Animal and Molecular Model Systems         Drosophila Forum         Yeast Forum         Zebrafish Forum         Botany Forum         C Elegans Forum         Arabidopsis and Plant Biology         Microbiology Forum         Knockout Mouse Forum     Chromatography Forum Products and Vendor Discussion     Molecular Biology Products and Vendors         Bad Product/Service? Post Here         Lab Equipment Discussion and Reviews Regional Molecular Biology Discussion     Forum Chemie     Forum Biologie     Forum Biologia     Forum Chimica     Forum Physik     Forum De Chimie     Forum De Physique     Forum Chemia     中国人分子的生物学论坛 Chinese     Greek Molecular Biology Forums     分子生物学のフォーラム Japanese     ميدان فارسى. Persian Molecular Biology     [أربيك] علم ساحة- Arabic     Forum de Biologie Moleculaire     Forum Biologia Molecolare     Forum die Molekularbiologie     Foro Biologia Molecular

 Similar Threads Thread Thread Starter Forum Replies Last Post johnlawrencereedjr Physics Forum 14 09-08-2008 12:47 AM Jan Gooral Physics Forum 0 05-22-2008 02:53 PM Jan Gooral Physics Forum 0 05-22-2008 02:52 PM Consc Physics Forum 16 12-27-2004 10:45 AM cinquirer Physics Forum 24 11-19-2003 12:09 PM

All times are GMT. The time now is 10:05 PM.

 Contact Us - Molecular Biology - Archive - Privacy Statement - Top