Magnet Myths and Misconceptions

[TinselKoala]

Iron Filings are a VERY Bad control and should not be used! They only are used by amateurs that simply don't know any better!

Reason: it's the same as two wires carrying current in the opposing directions can not lay parallel together! The Spins repel each other. As a result they are repelled from each other! This means the take an alternate path. That's why Iron Filings are So Much Denser on the Poles that in the centre of the Magnet!

What you mean is that iron filings REFUTE your silly contention, so they should not be used!

Don't you even realize how your green film works? Clearly not. It is showing you exactly the same thing that the iron filings are showing you, because basically that is what it is. What you are calling a "Bloch Wall" is the area where the embedded ferromagnetic particles in the film are presenting a different surface to you than they are at the "poles" of the magnet. Every magnetic field modelling software, every engineer who designs things like motors and generators that work, will be in agreement with MH on this topic, and will just be laughing at you. The green film is just a convenient way of using "iron filings" and you are completely  misinterpreting what it is telling you.

The Coriolis effect has ZERO, nothing at all, to do with magnetic fields. Nothing, zip, nada. If the Earth did not rotate there would be no Coriolis effect. If the Earth's magnetic field were to flip or disappear altogether, the Coriolis effect would still happen just as it does now, as long as the Earth rotates.

Your Reason is also false. The iron filings are more dense at the "poles" of the magnet because the field is concentrated there. The iron filings are bits of material with high permeability which means, in real science-speak, that they provide an easier path for the field than does empty space or air. The iron filings trace out the field direction by their orientation, and the field strength by their concentration.

Parallel current carrying wires have magnetic field lines that are circular around the wire. This field does not "spin". If you draw out the vectors which represent these circular field lines you will see... no, scratch that, because you only see what you want to see. Anyone who really can observe, will see that the vectors describe the repulsion or attraction, depending on the current direction, just as they do in a normal magnet.

[TinselKoala]

Chris:

So, are you suggesting that the equator on the earth is a sort of Bloch wall for the planet then?  I understand your points about the Coriolis effect and I do agree since this equates with what I was taught.

Interesting...I will have to think about this....

Bill

Where did you ever learn that the Coriolis effect has anything to do with magnetism? I'd like to see that reference, please.

There is no magnetic "equator" to the Earth in the same sense as the rotational equator. There is an approximate zone where the Earth's field is maximally parallel to the surface and this is what is called the "magnetic equator", equidistant from the _magnetic poles_. The magnetic poles, as you know, are not in the same location as the rotation poles of the Earth. The Coriolis effect depends on the Earth's rotation _only_, not magnetism.  The Earth's field has the same kind of orientation as the field from a sphere magnet, roughly. Near the magnetic poles, the "dip" (magnetic inclination) is such that the field points nearly up and down, which is why conventionally-mounted magnetic compasses don't work too well; they want to point down or up rather than swivelling in the horizontal plane. Near the middle of the field, that is approximately along the Earth's rotational equator, the "dip" is horizontal and magnetic compasses work the best.
http://en.wikipedia.org/wiki/Magnetic_dip
http://en.wikipedia.org/wiki/Coriolis_effect

[MileHigh]

Chris:

Iron Filings are a VERY Bad control and should not be used! They only are used by amateurs that simply don't know any better!

Reason: it's the same as two wires carrying current in the opposing directions can not lay parallel together! The Spins repel each other. As a result they are repelled from each other! This means the take an alternate path. That's why Iron Filings are So Much Denser on the Poles that in the centre of the Magnet!

Did you look a Tinman's linked clips?  They are great.

Your argument against iron filings doesn't hold water.  What do you mean by a spin?  What do you mean by an alternate path?

Look, everything related to magnetic field generation stems from one elemental thing - the magnetic field of a moving point charge.  This can easily be derived on paper using logic and mathematics.  The iron filing patterns just confirm for us visually what we know is there already from deductive reasoning.  There is no such thing as a north pole or a south pole.  There is no such thing as a Bloch Wall in a bar magnet.  There is just moving point charges and the associated magnetic fields that they produce.  Every moving point charge generates a magnetic field that undergoes vector addition with the magnetic fields generated by all the other moving point charges.  A bar magnet is nothing more than a brick of trillions of moving point charges generating a larger magnetic field.

Here are two clips that lay it all out for you:

https://www.youtube.com/watch?v=waTF7kjmmt8
https://www.youtube.com/watch?v=6xrUPxWfVvk

That's really all there is when you distill it down to it's bare essence.

You have now had several opportunities to make your case and state it on your terms.  You have been given the opportunity to discuss a fly-through of your model of a bar magnet but you have avoided that.

So what have you stated:  There is a Coriolis force because of the spinning Earth??  That has nothing to do with what we are even talking about.  You talk about being scientific.  You are supposed to discuss how a magnet works and your response is to talk about the Corillis force and how hurricanes spin in different directions in the Northern and Southern Hemispheres. Does that sound scientific to you?

Sorry but you haven't made your case at all.  Do you see that also?  There is no substance to your argument at all.

My suggestion to you is to rethink all of this stuff out in your head again and to get up the learning curve.  All of your experiments will still be the same with the same results, but hopefully you will have the proper insight.

MileHigh

[allcanadian]

Couple interesting photo's.
The first is a science project my 10 year old son did proving the iron filing experiment found in every textbook is incorrect. The filings align forming lines due to magnetic induction which he showed on a larger scale with short suspended iron wires. It is not a true representation of the magnetic field it is an effect produced by magnetic induction due to the presence of a magnetic field. Magnetic viewing film is simply smaller pieces of iron suspended in a film and ferrofluid even smaller iron particles. The scale of the particles may change however the effect of magnetic induction is the same.


The second picture is a bar magnets field captured using neutron spin, I believe, which is a more true representation of the field in my opinion. The reason for the curvature in my opinion is leakage, take one magnet and the field curls back on itself...the dipole field. Take two magnets together and the main field curls back plus each individual field of each magnet also curls back as flux leakage. Now take millions of dipole fields combined to produce the main field but all produce flux leakage in themselves which forms a field distortion. Obviously flux lines cannot cross because there are no lines in reality and it is a simple effect produced my magnetic induction. However the field can be distorted in the near field which is perfectly acceptable according to the laws we know.


The thing to remember is we know flux leakage occurs and we also know every magnetic field we see is the combined effort of many smaller magnetic fields. So why would we presume flux leakage occurs on one level but not the other?.


AC

[MarkE]

Looks like they aren't the only ones doing that. Funny how iron filings don't show that pinch at the waist, isn't it.

I would say: stunning, yes.  I invite any of them to show that the curl at the center that they claim exists, but which soft magnetic material does not seem influenced by does not diminish as a dipole gets longer.