Paradox in Electromagnetism?

[metacogitans]

Say you have an iron ball set in a chamber, with a row of electromagnets on one side of the chamber wall; Each electromagnet switches back and forth between emitting a positive or negative electromagnetic field into the chamber, and the row is setup so that each electromagnet emits an oppositely charged electromagnetic field into the chamber from the electromagnet(s) next to it.

 

Now, here is the paradox: Will the iron ball ultimately roll towards or away from the row of electromagnets?

 

My intuition would suggest that the electromagnets would cancel each other out -- or that imperfections in the construction of the setup would lead to a favored outcome. But, my hypothesis is that the majority of the time, attraction would be favored, as a repulsive effect can only result in momentum to the side of where the repulsive field is strongest in the chamber and into the path of an attractive field instead; as the waves from the source of a repulsive field spread as they propagate, with small imperfections in the setup causing the iron ball to be repulsed to one side or the other instead of staying centered with the source of the field.

Edited December 27, 2015 by metacogitans

[ajb]

Say you have an iron ball set in a chamber, with a row of electromagnets on one side of the chamber wall; Each electromagnet switches back and forth between emitting a positive or negative electromagnetic field into the chamber, and the row is setup so that each electromagnet emits an oppositely charged electromagnetic field into the chamber from the electromagnet(s) next to it.

 

You need to explain this much more clearly. For example 'positive or negative electromagnetic field' and 'oppositely charged electromagnetic field'.

 

The electromagnetic field carries no electric charge.

[metacogitans]

 

 

You need to explain this much more clearly. For example 'positive or negative electromagnetic field' and 'oppositely charged electromagnetic field'.

 

The electromagnetic field carries no electric charge.

Is this secretly a challenge to see if I can be consistent in giving an explanation for all of electromagnetism without saying something that I need to be corrected on?

 

- Charged particles produce an electromagnetic field. Similar charges repel; opposite charges attract.

- Composite particles usually have a 'polarity' resulting from the geometric orientation of their constituents.

- Polarity results in magnetic attraction/repulsion between composite particles.

- In ferromagnetic compounds, molecules share polarity to a significant extent that repulsion/attraction can be demonstrated at our macroscopic scale.

- By running current through a coiled conductive wire, a magnetic field is created with a north/south

- The north/south can be reversed by switching the end used as input for the current.

 

Now you answer my question

( )

 

... I just know I'm going to have to make drawings in microsoft paint to describe my 'experiment' in the original post. Here, I'm going to try doing it in just text first:

 

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- > repulsive electromagnetic effect here < (-|+) <-- iron ball

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^electromagnets

 

Because the iron ball can't be precisely centered with the negative electromagnet, the repulsion repositions the iron ball for attraction.

 

The catch is, the electromagnets switch back and forth between positive and negative.

My point however, or 'hypothesis' if you will, is that no matter how quickly the electromagnets are switching between positive and negative, or the strength of the electromagnets, the iron ball will favor attraction towards the row of electromagnets -- or, if the electromagnets are too weak, it will not move at all. Repulsion will never be favored - hence, the paradox: attraction is dominant when immediate intuition would tell us they balance out.

 

Or am I wrong? I am posting this thread as a question; I'd really like to know if/why that's not true.

 

There is a reason for this thought experiment; I'm wondering if electromagnetism can be used to explain gravity. Take the Earth for example, every proton and neutron is by itself already polar, having multiple constituents with different charges (up and down quarks). The sum of all particles making up the Earth then could be thought of as a large number of electromagnets -- as they move around, they could be compared to the shifting electromagnets in my example. A particle near Earth, influenced by all the particles making up the Earth which act as little electromagnets, would have a net result of electromagnetic attraction - as attraction is favored.

Edited December 27, 2015 by metacogitans

[ajb]

Is this secretly a challenge to see if I can be consistent in giving an explanation for all of electromagnetism without saying something that I need to be corrected on?

You have phrased something wrong in your opening post. That is all. You should think about this, it may make it clearer to all of us what you are actually asking about.

 

 

- The north/south can be reversed by switching the end used as input for the current.

Okay, that is starting to make more sense.

 

Your set up is that of an iron ball and two rows of coils that you use to induce a magnetic field. The polarity of the magnetic field of a coil is determined by the direction of the current. Thus as you have two parallel coils you can align the polarities or anti-align them.

 

Is this a similar to switching between Helmholtz coil arrangement and the quadrupole magnetic field?

 

http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magquad.html#c2

[Strange]

My intuition would suggest that the electromagnets would cancel each other out -- or that imperfections in the construction of the setup would lead to a favored outcome. But, my hypothesis is that the majority of the time, attraction would be favored, as a repulsive effect can only result in momentum to the side of where the repulsive field is strongest in the chamber and into the path of an attractive field instead; as the waves from the source of a repulsive field spread as they propagate, with small imperfections in the setup causing the iron ball to be repulsed to one side or the other instead of staying centered with the source of the field.

 

I don't know why you would expect any repulsion. An iron ball is attracted equally to a north and a south pole.

(Edit, unless the changing fields are inducing currents in the ball giving it some magnetism ... But then I imagine it becomes very difficult to calculate what will happen.)

 

But as all the magnets average out to zero overall, there will be no force. You will only get a small attractive force if the ball is close enough that it is closer to one of the N or S poles and the others don't quite cancel it out.

- Charged particles produce an electromagnetic field. Similar charges repel; opposite charges attract.

 

An electric field.

 

I know you don't want to be corrected, but it is a good way to learn. You seem to be mixing up electric charge and magnetism.

 

- Composite particles usually have a 'polarity' resulting from the geometric orientation of their constituents.

 

I guess you mean a dipole moment? A slight excess of charge on one side than the other.

 

- Polarity results in magnetic attraction/repulsion between composite particles.

 

Electrostatic, not magnetic. Unless they are moving, in which case there will be a magnetic field as well.

 

There is a reason for this thought experiment; I'm wondering if electromagnetism can be used to explain gravity.

 

No, for several reasons.

Electric (and magnetic) fields can be screened, gravity can't.

Gravity is not proportional to electric charge but to mass.

Magnetism falls off with a cube law, not a square law. (And for the force due to a dipole moment as well, I think.)

Even if there is a dipole moment at the atomic/molecular level that does not apply at the scale of the Earth. Everything is oriented differently and they all cacnel out.

Even if the force did follow an inverse square law, the best it could do is model Newtonian gravity, not the real world.

 

Edited December 27, 2015 by Strange

[studiot]

 

strange

But as all the magnets average out to zero overall, there will be no force

 

Even if there is an odd number of magnets?

 

With all the changing of field, I am not sure if a linear array would produce a strange attractor, I would expect there to be a chaotic frequency doubling at some frequencies of operation.

[ajb]

... I just know I'm going to have to make drawings in microsoft paint to describe my 'experiment' in the original post.

I think that would help everybody.

[Strange]

Even if there is an odd number of magnets?

 

I assumed there were. Otherwise the question becomes a bit pointless.

[metacogitans]

Here is the setup; the end of the coil used as input switches at periodic intervals, switching north and south.

 

In the next image, the black dot represents the imaginary 'point of contact' with the center of the iron ball, and the black arrow is the general direction the ball would travel during that instant of the wave affecting it.

 

This direction is always 'to the side', and hence into another electromagnet's 'lane' in the chamber where that electromagnet is most influential.

Other things worth noting:

- The iron ball realistically can't have an exact north and south, and the distribution of polarity throughout the ball is uneven - which means it would likely 'wobble' when moving through the chamber.

- If the intervals when the electromagnet's north/south switches were timed right, the north/south end of the ball would move into a different position right as the electromagnets would switch leading to repulsion, and this may cause repulsion to be 'favored' for several intervals, but I would still suspect it to ultimately favor attraction.

- As the iron ball gets closer to the electromagnets, the stronger their effect on the momentum of the iron ball, while the further away the iron ball gets, the weaker the effect. Attraction might also be favored for this reason, as it would gain more momentum from the magnets the closer it is. Although, this could actually lead to repulsion ultimately being dominant, as if the ball rolls too far away, the magnets wouldn't be strong enough to get it to roll back towards them.

- Variables like the size of the coils and the ball, the weight of the ball, the strength of each electromagnet, the number of coils, how frequently the electromagnets switch between north and south, how far the ball is placed etc., would likely lead to varied results, with some favoring repulsion. What I think would be most interesting though would be variations where the iron ball is moving around in the chamber for some time before either attraction or repulsion becomes apparently dominant.

 

The paradox is if attraction is favored more often than repulsion, but I suppose that isn't really a paradox, as magnetism fundamentally arises from the geometric orientation of charged particles, and attraction/repulsion are dependent variables. So attraction is not being 'favored', it is just north/south re-positioning themselves.

 

 

No, for several reasons.
Electric (and magnetic) fields can be screened, gravity can't.
Gravity is not proportional to electric charge but to mass.
Magnetism falls off with a cube law, not a square law. (And for the force due to a dipole moment as well, I think.)
Even if there is a dipole moment at the atomic/molecular level that does not apply at the scale of the Earth. Everything is oriented differently and they all cacnel out.
Even if the force did follow an inverse square law, the best it could do is model Newtonian gravity, not the real world.

But if the combined electromagnetic activity of the entire planet is composed of discrete particles with either a positive/negative charge, then considering a particle in space, wouldn't the particle's tendency be to move out of line with similar charged particles and in line with oppositely charged particles, resulting in attraction?

Since repulsion always moves something "to the side" slightly, wouldn't repulsion always move a particle into line with an oppositely charged particle where attraction is occurring?

In fact, wouldn't particles do this anyways following a path of least resistance?

 

Also, what do you mean by cube law and not square law? Isn't it square-cube law and inverse-square law?

 

And we only know gravity is proportional to mass from observations made at a macroscopic scale. But is there actually any evidence that charge doesn't effect gravity? Also, we could equivocate units of mass to include charge by looking at an object's molar mass and getting a number of particles.

 

I don't know. I started wondering about it after thinking that the results of the 1919 solar eclipse experiment could be explained as the diffraction of light as it passes through the sun's corona. The more I think about it, there are other problems with 'warped space-time' as an explanation for gravity, like it would lead us to assume that objects would fall faster if they're at a higher temperature, since the 'movement' from the thermal energy of the particles would be faster-farther through warped space-time in the direction of a massive body.

An electric field.

I know you don't want to be corrected, but it is a good way to learn. You seem to be mixing up electric charge and magnetism.

Since it is all a product of the same fundamental force 'electromagnetism', aren't all electric fields and all magnetic fields technically 'electromagnetic' fields as well? I understand the addition of the word 'magnetic' when the magnetic effect is something different is confusing, but what else am I supposed to call it when talking about the electromagnetic force in general?

It's just a technical inconsistency of language, like If someone were talking about a new model for Kaluza-Klein theory with some variation to the equations involving quantum mechanics, you could still say he is talking about "Kaluza-Klein theory" even though Kaluza had nothing to do with the addition of quantum mechanics to the theory.

Edited December 28, 2015 by metacogitans

[studiot]

Your information provides no sense of scale so I cannot follow the connection between iron balls rolling around in chambers and planets and their gravity.

You have to consider the time lag between the change in the magnets' field and the ball.

[Strange]

- The iron ball realistically can't have an exact north and south, and the distribution of polarity throughout the ball is uneven - which means it would likely 'wobble' when moving through the chamber.

 

Why would the ball be magnetised? And what if it isn't? What if it is made of rubber, rather than iron?

 

 

- If the intervals when the electromagnet's north/south switches were timed right, the north/south end of the ball would move into a different position right as the electromagnets would switch leading to repulsion, and this may cause repulsion to be 'favored' for several intervals, but I would still suspect it to ultimately favor attraction.

 

Why not do the calculations to find out?

 

(Maybe you will say, "but that's why I am asking". But as you are rejecting answers you don't like, perhaps the only way you will be convinced is if you work it out for yourself.)

 

 

Since repulsion always moves something "to the side" slightly

 

Why do you think that?

 

 

Also, what do you mean by cube law and not square law? Isn't it square-cube law and inverse-square law?

 

"Far away from a magnet, the magnetic field created by that magnet is almost always described (to a good approximation) by a dipole field characterized by its total magnetic dipole moment, m. This is true regardless of the shape of the magnet, so long as the magnetic moment is non-zero. One characteristic of a dipole field is that the strength of the field falls off inversely with the cube of the distance from the magnet's center."

https://en.wikipedia.org/wiki/Force_between_magnets#Magnetic_dipole_moment

 

 

And we only know gravity is proportional to mass from observations made at a macroscopic scale.

 

Your whole argument is about macroscopic scales.

 

 

But is there actually any evidence that charge doesn't effect gravity?

 

Sorry, it doesn't work like that. What evidence do you have that charge affects gravity?

 

 

Also, we could equivocate units of mass to include charge by looking at an object's molar mass and getting a number of particles.

 

There is no relationship between mass and charge.

 

 

I don't know. I started wondering about it after thinking that the results of the 1919 solar eclipse experiment could be explained as the diffraction of light as it passes through the sun's corona.

 

That experiment is not worth considering. Arguably, it didn't make measurements accurate enough to confirm relativity. It is only of historical interest. Perhaps you should look at more modern experiments. The Pound-Rebka experiment is good (as an example of brilliant experimental design, if nothing else). But of course there are plenty of more recent observations of gravitational lensing, as well.

 

 

Since it is all a product of the same fundamental force 'electromagnetism', aren't all electric fields and all magnetic fields technically 'electromagnetic' fields as well? I understand the addition of the word 'magnetic' when the magnetic effect is something different is confusing, but what else am I supposed to call it when talking about the electromagnetic force in general?

 

You are not talking about the "electromagnetic force in general" (if there is any such thing). You are talking about magnetic forces sometimes and sometimes electrostatic forces, in a very confused way.

 

By the way, this idea is not very original so it is not as if people haven't considered all the reasons why it doesn't work. But as you are not willing to accept what other people tell you (which is commendable) then you need to do the math yourself.

[metacogitans]

 

Why would the ball be magnetised? And what if it isn't? What if it is made of rubber, rather than iron?

 

Those are just the parameters of the thought experiment...

 

 

 

Why not do the calculations to find out?

 

 

The calculations for just one variant of the setup won't provide insight for all variants; we would have to make calculations for numerous variants of the setup to begin deducing the overall tendency, and we would realize it would have been easier just to look at the mathematical concepts themselves to figure out the overall tendency. With extreme conditions, the iron ball will either immediately get stuck against a coil or be too far away for the electromagnets to cause the ball to roll.

 

But when the conditions are right for the iron ball to switch between rolling away from the direction of the electromagnets and towards the directions of the electromagnets, The majority of variants in the setup would favor attraction - that's my assumption anyways.

 

 

Why do you think that?

I guess it only applies to magnetic repulsion, not all repulsion.

 

 

Your whole argument is about macroscopic scales.

No in the part of my post where you are quoting me here. I am also considering the scale of individual particles. But what does that have to do with my 'argument' anyways?

 

 

Sorry, it doesn't work like that. What evidence do you have that charge affects gravity?

If we were able to conduct an experiment where we measure the gravitational attraction between two clouds of electrons in space, there would be evidence if we measured there to be no gravitational attraction occurring between them.

 

 

 

There is no relationship between mass and charge.

Since a value for mass is determined by a number of particles, then there is a relationship between charge and mass. If the overall charge of an object increases or decreases, then the number of particles in the object will have changed - so there has to be some relationship.

 

 

You are not talking about the "electromagnetic force in general" (if there is any such thing). You are talking about magnetic forces sometimes and sometimes electrostatic forces, in a very confused way.

 

In the text at the root of the chain of quotes, I said 'charged particles produce an electromagnetic field'.

Since you quoted wikipedia, I get to as well:

 

Static E and M fields and static EM fields

"When an EM field (see electromagnetic tensor) is not varying in time, it may be seen as a purely electrical field or a purely magnetic field, or a mixture of both. However the general case of a static EM field with both electric and magnetic components present, is the case that appears to most observers. Observers who see only an electric or magnetic field component of a static EM field, have the other (electric or magnetic) component suppressed, due to the special case of the immobile state of the charges that produce the EM field in that case. In such cases the other component becomes manifest in other observer frames.

 

A consequence of this, is that any case that seems to consist of a "pure" static electric or magnetic field, can be converted to an EM field, with both E and M components present, by simply moving the observer into a frame of reference which is moving with regard to the frame in which only the “pure” electric or magnetic field appears. That is, a pure static electric field will show the familiar magnetic field associated with a current, in any frame of reference where the charge moves. Likewise, any new motion of a charge in a region that seemed previously to contain only a magnetic field, will show that that the space now contains an electric field as well, which will be found to produces an additional Lorentz force upon the moving charge."

 

https://en.wikipedia.org/wiki/Electromagnetic_field#Static_E_and_M_fields_and_static_EM_fields

 

Edited December 29, 2015 by metacogitans

[Strange]

But when the conditions are right for the iron ball to switch between rolling away from the direction of the electromagnets and towards the directions of the electromagnets, The majority of variants in the setup would favor attraction - that's my assumption anyways.

 

But your assumption seems to be baseless. Which is why I suggest doing the calculations. Why not start with the simplest case of a single electromagnet switching direction?

 

I guess it only applies to magnetic repulsion, not all repulsion.

 

Why do you think it applies to magnetic repulsion? Why do you think there is a lateral component?

 

No in the part of my post where you are quoting me here. I am also considering the scale of individual particles. But what does that have to do with my 'argument' anyways?

 

You seem to be saying that gravity is / could be caused by electric (and/or magnetic forces). Gravity is (mainly) significant between massive objects, therefore you can't dismiss evidence form those scales as being irrelevant.

 

(BTW I am using the word "argument" in the sense of "a series of statements made to support a position", not a violent disagreement. But I found out recently that not everyone uses it in this way.)

 

If we were able to conduct an experiment where we measure the gravitational attraction between two clouds of electrons in space, there would be evidence if we measured there to be no gravitational attraction occurring between them.

 

In other words, you have no evidence. (Although what you describe sounds a bit like the Millican experiment to measure electron charge.)

 

In the text at the root of the chain of quotes, I said 'charged particles produce an electromagnetic field'.

Since you quoted wikipedia, I get to as well:

 

That seems to confirm that (a) electric and magnetic fields are different things and (b) moving charges produce a magnetic field.

[swansont]

 

Since a value for mass is determined by a number of particles, then there is a relationship between charge and mass. If the overall charge of an object increases or decreases, then the number of particles in the object will have changed - so there has to be some relationship.

 

So what is this relationship? Let's have an equation that determines the charge that's a function of mass.

[MigL]

Assuming things worked as you say and the iron ball experienced a tangential force from the switching, alternating electric or magnetic fields such that attraction ALWAYS prevailed.

And assuming the switching alternating fields represented a massive body ( like the Earth ), what exactly is switching/alternating on the earth to produce gravity?

And we can measure the gravitational attraction of a small iron ball. Are there switching/alternating fields originating from the iron ball as well ? Because that makes your model a lot more complex.

And don't forget that the separation of the fields relative to the size of the ball will have varying effects, how does your gravitational model take this in consideration ?

How is the field switching frequency accounted for ? That also affects how quickly the iron ball reaches the 'prevailing' attractive state.

 

Instead of wasting your time thinking about how all these conflicting effects can model gravity, you should instead consider how effectively curved space-time does it. The math defining the model may be complex, but the theory is essentially simple.

( unless you're considering this as a thought experiment to hone your thinking and math skills, which isn't useless at all )