Paradox in Magnatism?

[alan2here]

As I understand magnatism as with electric feilds, electromagnetic waves and graverty all conform to a rule that states that the force acted on an object by the source (planet\magnet ect...) is equal to the inverse square of the distance away from the source that the object is.

 

Ferrite magnets are week whereas neodym magnets are relitivly much stronger.

 

Magnets use ferromagnatism to interact with each other. There is also another force I think called paramagnatism that is a metal object that is not itself a magnet being atracted to magnets.

 

Mostly thease two forces seem to act as once force. However there is one instance where they can be seen together acting in opisite directions.

 

Push two ferrite magnets together with the same poles (e.g north and north) and they will not remain together after you stop pushing, this is because they repel each other. The same happens with neodym magnets (only this is much harder to do).

 

However push one neodym and one ferrite magnet together (of same poles) and they only repell up to a point, beyond that point they attract. Once pulled apart enough they then repell each other again. This can be done for any size combination.

 

My question is that is if:

 

_Both forces use inverse squared to define force over distance

_Both are acting apon the same magnet (therefore of the same size)

and

_One is weeker than the other (paramagnatism is weeker than feromagnatism)

 

Then how come the weeker one seems to cause a pull only at verry close distances. It would make more sence that the stronger force should win out at all distances?

[John Cuthber]

I think the inverse square law cannot be applied to magnets (except monopoles, and they don't seem to exist).

[insane_alien]

its an inverse cubic law for magnetic dipoles

[alan2here]

So you are saying that the magnatism linking the north and south poles of magnets with other magnets (feromagnatism) uses the inverse cubic law?

[Teotihuacan]

What happens to the formula, when the distance is Zero?

 

There is no field to propogate between the magnets, but between the various molecules themselves.

 

This causes the weaker aligned molecules to "flip" over. Essentially reversing the poles. The repulsion is still there, only this time on a molecular level, altering their alignment within the metallic lattice rather than the physical object being displaced.

 

If you can measure the strength of magnetic flux afterward, it should be weaker in both magnets because of this scattering effect or degaussing. Similarly, two magnets together will gather strength by enhancing each other's molecular alignment. A "keeper" on a horseshoe magnet does a similar purpose, because without it, the earth's geomagnetic force field will degauss it, over time.

 

btw... there are lots of magnetic metals, besides iron (fer in latin).

[alan2here]

What happens to the formula, when the distance is Zero?

 

There is no field to propogate between the magnets, but between the various molecules themselves.

 

This causes the weaker aligned molecules to "flip" over. Essentially reversing the poles. The repulsion is still there, only this time on a molecular level, altering their alignment within the metallic lattice rather than the physical object being displaced.

Iv'e heard the turm "pole reversal" before but to me it dosn't seem to describe whats happening. It seemed to be two forces acting againsed each other (the magnetic attraction to a metal and the magnetic effect againsed another magnet). However I do understand what you mean now.

 

 

A "keeper" on a horseshoe magnet does a similar purpose, because without it, the earth's geomagnetic force field will degauss it, over time.

Looking at the feild lines reveals a nice loop with a horseshoe + keeper. Apparently the worst shape is a long rod for bad magnetic permibility (Loosing magnatism over time). I think the loss of feild over time must be fairly small.

 

 

there are lots of magnetic metals

I know there are lots of metals but Ferrite and NIB seem to be the only two worthwhile ones unless you need them to go >80 degrees C. Even then NIB can be made to work well. However I do see how Iron magnets could be usefull. Horseshoe for example only seems to come in Iron.

[Externet]

The main misconception and misunderstanding of magnetic interaction is caused by the asumption above ...." What happens to the formula, when the distance is Zero?"...

 

The distance is never zero

 

Because the poles are not points in the magnets; the pole are zones within the magnets.

And they are inside, never at the ends, usually spaced at ~4/5 of the lenght of the magnet.

 

Attempting to make a void in the zone of the poles, as to reduce the distance, does not work. The poles partially re-locate around the void.

 

Otherwise, the distance between two magnet poles, if somehow became zero, the force of attraction/repulsion would be infinite.

 

Miguel

[Rocket Man]

if you get close to zero distance, you start seeing the poles on the electrons appreciably separated, try to get closer, you start seeing the electrons as wave forms with no discernable position according to the uncertainty principle.

 

there's not really any thing paradoxical in magnetism, if you start drawing up rules for the marcoscopic, you'll find breaches every where. start by saying "magnetisim is due to motion of charged particles" then study the causes of ferromagnetism, diamagnetism, and all sorts of other effects. you'll find that when the microscopic is correct, the macroscopic behaves itself.

 

a magnetic feild is a feild. it doesn't have a fixed relationship with distance.

it took a brilliant mathmatician to prove that spherical bodies can be simplified to a point like source of gravity and net static charge. taking those for granted is a big mistake in the realm of magnetism.

[alan2here]

What happens to the formula, when the distance is Zero?

I think he ment when the ends of the magnets are touching.

This is explained in his next paragraph and is regarding the "pole reversal" effect.

 

 

Because the poles are not points in the magnets; the pole are zones within the magnets.

And they are inside, never at the ends, usually spaced at ~4/5 of the lenght of the magnet.

 

Attempting to make a void in the zone of the poles, as to reduce the distance, does not work. The poles partially re-locate around the void.

 

Otherwise, the distance between two magnet poles, if somehow became zero, the force of attraction/repulsion would be infinite.

Thanks for the insight :¬)