What is the force that moves electrons?

[madhatter106]

Okay this may sound like a simple question but I can't help but feel that the answer is circular. a voltage potential will have an accumulation of charge but that's only descriptive of what is happening. there is the more common electromagnetic component vs the electrostatic one.

If there is a voltage potential between two surfaces and the charge is imbalanced, what caused the electrons to move? what is the force that moves electrons?

Does the electron for example only change the charge density up/down and this imbalance cause the subsequent imbalance in the nearby electrons? in that the electrons don't actually move off the conducting plate but influence the electrons and protons to create a cascade like effect that induces the voltage potential to change. more of a 'vibrating' analogy really.

last one here, since like charges repel and unlike attract how is it that an imbalance can be built up? more of a fundamental question, the permittivity is just a descriptive of the phenomenon of building up the imbalance until the insulator breaks down, but is that really what is occurring? is this imbalance potential related the fundamental force that moves the electron/proton?

 

[Terocamo]

Do you mean the E field created by the power source?

 

[madhatter106]

Do you mean the E field created by the power source?

No, it's the question of what force causes the electron charge to build so that there is an imbalance. The mechanical force on an object translates to imbalance, or in a uniform field both the B and H are induced to move but with what force?

In a cathode/anode there is a displacement of the atoms and a loss/gain of mass. In an electrostatic charge there isn't the same loss/gain but an imbalance that can be sustained as long as the induced force is kept constant.

electrohydrodynamics is another interesting one as well, the low electroconductivity of the fluid in relation to surface area and velocity will create and charge imbalance and rise in voltage potential. the prevailing similarity is a displacement and time component and this seems to be the 'force' that moves the electron or proton to build an imbalance. this potential rise should occur in steps so that at a specific delta of velocity there is no imbalance but then crossing that point there is an imbalance created. the density of the fluid is significant in this effect as well as its conductivity so a conductive fluid of greater than 50 picosiemens would not work.

take lighting as another example, huge potentials that are not fully understood.

maybe this falls more into the QED field and the reason why it may not have an answer yet.

 

[Terocamo]

Maybe I am not following your idea. But I think the force that would maintain an imbalance of charges in a circuit is the force caused by the electric field along the wire. This electric field is generated by a power source which move the electrons (charges) along the circuit until the imbalance charge can generate an electric field large enough to counter the effect of the power source.

Well, that is what I have learnt, and I am far from an expert. I have completely no idea what electrohydrodynamic is. So I guess I will just give it a try. XD

 

[madhatter106]

I see the problem with my question, it's not specific enough to separate out what appears to me as circular.

saying that the B or E field is the fundamental force is stating that it's self-inducing which it isn't. the field has to be generated what force is moving the electron or proton potential from it's initial state? is it an increase in the strong force? I know this gets into QCD but I don't recall it referring to the potential rise in accumulated charges to field.

 

[Pythagorean]

There is no particular force associated with the motion of the electron. Any force can move the electron, just like any sufficient force can move any mass; it only needs to be applied to the object.

In most every-day physics situations, it's the gravitational or electromagnetic force. Gravity pulls on electrons and protons because they both have mass. The em force acts on the electron because it has charge.

saying that the B or E field is the fundamental force is stating that it's self-inducing which it isn't.

how do you figure that?

the field has to be generated what force is moving the electron or proton potential from it's initial state?

Charged particles already generate electric fields without being moved. Any arbitrary force can move an electron. Once it starts moving, it generates a magnetic field. The magnetic field was not part of the initial motion.

This is why induction motors can't be run as generators without putting a current through one of the coils (current is moving charge). Some motion has to be generated by an outside force first, before the induction will work in an effective way. The outside force can be electromagnetic, but it doesn't come from the same field you generate once you move the particle.

 

[tiny-tim]

hi madhatter106!

If there is a https://www.physicsforums.com/library.php?do=view_item&itemid=301" potential between two surfaces and the charge is imbalanced, what caused the electrons to move? what is the force that moves electrons?

ultimately, it's whatever produces the voltage …

in a standard battery cell, a chemical reaction (oxidation, i think) causes electrons to go from the thingy to the wotsit, other electrons flow in from all round the circuit to replace the missing ones, and so it's that chemical reaction energy which drives the whole circuit

(dunno why the reaction happens though … probably something to do with molecules getting into a lower energy state )

 

[Jack the Stri]

hi madhatter106!


ultimately, it's whatever produces the voltage …

in a standard battery cell, a chemical reaction (oxidation, i think) causes electrons to go from the thingy to the wotsit, other electrons flow in from all round the circuit to replace the missing ones, and so it's that chemical reaction energy which drives the whole circuit

(dunno why the reaction happens though … probably something to do with molecules getting into a lower energy state )

Yep, that all depends on electrochemical potential, and as with any reaction it results in a lower energy state (and/or a higher entropy but let's not get into that).

 

[madhatter106]

There is no particular force associated with the motion of the electron. Any force can move the electron, just like any sufficient force can move any mass; it only needs to be applied to the object.

In most every-day physics situations, it's the gravitational or electromagnetic force. Gravity pulls on electrons and protons because they both have mass. The em force acts on the electron because it has charge.



how do you figure that?



Charged particles already generate electric fields without being moved. Any arbitrary force can move an electron. Once it starts moving, it generates a magnetic field. The magnetic field was not part of the initial motion.

This is why induction motors can't be run as generators without putting a current through one of the coils (current is moving charge). Some motion has to be generated by an outside force first, before the induction will work in an effective way. The outside force can be electromagnetic, but it doesn't come from the same field you generate once you move the particle.

It's the arbitrary force that is in question, what is it? in regards to the EM analogy the mechanical work is the force that moves the EM field over time and that gives rise to the potential. amperes circuital law. but that doesn't explain why the physical movement gave rise to that potential.

In Gauss's flux for the electric field the field is not uniform a dielectric surface will have a uniform field and thus down the rabbit hole we arrive at displacement current from Maxwell. It seems odd that a simple physical macro force can easily move the electrons yet the EM force is much greater. If the electrostatic potential is that simple to create why doesn't it always return to equipotentional before a charge build-up? as I understand it the permittivity or Maxwells original polarization of the dielectric is the resistance of the free E field, that would allow for an imbalance within free space and unlike the uniform surface a charge could be retained until that permittivity changed. so without any physical force the change in permittivity would change the potential without electron movement.

For some reason I then see the electron/proton movement in electrostatics and electromagnetic as a change in field charge and not a physical electron displacement movement. the charge is moving but the electron of that medium stays within the medium unless it's transferred by other electrodynamic interactions.

 

[Terocamo]

It's the arbitrary force that is in question, what is it? in regards to the EM analogy the mechanical work is the force that moves the EM field over time and that gives rise to the potential. amperes circuital law. but that doesn't explain why the physical movement gave rise to that potential.

I imagine that arbitrary force can be any kind of force.
Physical movement of a conductor is perhaps simular to the relative motion of free electrons in it.(just guessing XD)
Therefore it is the mechanical force causing the imbalance of charge because electron have mass and hence, inertia.

If you try to stick a rod of metal into water, the equilibrium of ion formation will also lead to a potential difference. In this case, it would be the electrostatic interaction between ions and water molecule and the electrons that give rise to the imbalance of charge.

I don't think strong interaction will have any effect on the movements of free electron because it is proven that it will only act within a very short distance.

It is quite acceptable to me that electrons move with charge and moved by electrostatic interaction. If the imbalance of charge is only due to the moving of charge, i don't think there will be thermoelectric or photoelectric effect, cause you think the electron never leave the medium.

 

[madhatter106]

I imagine that arbitrary force can be any kind of force.
Physical movement of a conductor is perhaps simular to the relative motion of free electrons in it.(just guessing XD)
Therefore it is the mechanical force causing the imbalance of charge because electron have mass and hence, inertia.

If you try to stick a rod of metal into water, the equilibrium of ion formation will also lead to a potential difference. In this case, it would be the electrostatic interaction between ions and water molecule and the electrons that give rise to the imbalance of charge.

I don't think strong interaction will have any effect on the movements of free electron because it is proven that it will only act within a very short distance.

It is quite acceptable to me that electrons move with charge and moved by electrostatic interaction. If the imbalance of charge is only due to the moving of charge, i don't think there will be thermoelectric or photoelectric effect, cause you think the electron never leave the medium.

OK, in just a purely physical movement context if in the case of liquids the conductivity is high enough then the ionic bond is fast and no build of electrostatic charge is transferred. from what I recall it's not a pure ionic bond as that's not possible but a mix of covalent and ionic. the infinite electronegative isn't possible so a pure ionic bond isn't -I have a bit of point here I think- given that there has to be an equilibrium in the electron bond any movement would be countered with that balance. so it seems that it comes down to the fundamental frequency step of the electron and it's energy state and another 'force' that gives rise to an ability to increase the charge imbalance or not in a given medium. that is why I have a hard time seeing the electron freely move between atomic structures i.e. conductor to dielectric. the ionization of a gas emits photons due to the energy and conservation of charge right? so the electron moves up/down handing the charge off so to speak as it returns to it previous state, if it was actually still moving in the direction of charge flow what force keeps it moving after it's given up that state?

 

[Terocamo]

In fact the phenomenon you mentioned is not something related to static electrons.
That is named as a covalent charator of an ionic bond.
However, this does not mean the electron is stationed between the ions, instead they are moving in a manner that no tools can determine it's position. Hence, we can only determine the relative electron density around the particles.
So there isn't any force that held the electron in the same position, but there is an imbalance of charge density due to the difference in the ability of the ions to attract the electrons. The electrons tend to stay longer around the ion with higher electronegativity, therefore the electron density is higher around that ion. I don't think there are force other than electrostatic interaction involved in such behavior. This is what I have came up with when referring the textbooks.