What is the Science Behind Electric Shock and Grounding?

[DarioC]

Nope, as in not. The electrons don't change state, or really move very far in any reasonable amount of time, they just bang against each other.

Did you look at the notes on my calculations. The base for those calculations was the known or calculated number of electrons that make up an Ampere that is pretty well accepted.

I have been learning as I go with this. You seem interested in satisfying a curiosity about what happens at the most basic level in a conductor, not the everyday rules that allow for predicting electrical behavior and designing circuits.

Electrons are the basic stuff to start with in a conductor, you know that. Electrons are known to have a charge that produces an electric field around them that interacts with the fields of other electrons. That is, the fields push against each other, I assume without the electrons touching.

There are a gazillion electrons in even a small short conducting wire. (See my previously noted calculations and comments.) My read is that you push an electron into a conductor and it will push against the fields of the other electrons, each one shifting a small amount, the shift in position propagating down the conductor at about the speed of light. When this shift in positions gets to the other end of the conductor, under certain conditions, an electron will be pushed out.

This visualization does not conflict with any electrical laws as far as I can tell. Of course you normally shove millions of electrons in via the pressure of an external electrical field and then millions pop out the other end of the conductor (if they have some where to go, like other conducting material with a scarcity of electrons, that is, a positive charge.) It still takes a very long time for a single electron to go from end to end of even a short wire. There is apparently also a lot of random motion in what would look like a sea of electrons.

The best analogy that I can think of is the line of metal balls hanging from strings where you bang one ball into the end of the row of balls and the ball at the other end of the row jumps away from the row and swings outward. Pretty close similarity.

I just deleted a part I had here about "free" electrons vs "loose" valence electrons. What I see on the internet doesn't work in all cases. Must be wrong.


The thing that we are stuck with, as a bottom line, is that electrons have a charge on them that produces an electric field around them that interacts with other physical objects. That is the basis of any explanation, and as far down a the basics can be reduced to.

No doubt the details can go on and on, but I am just tickled that there is a "classical" picture that I can see that doesn't step on the toes of the laws of electricity.

This discription works for an open ended conductor too.

DC

 

[RiddlerA]

There are a gazillion electrons in even a small short conducting wire. (See my previously noted calculations and comments.) My read is that you push an electron into a conductor and it will push against the fields of the other electrons, each one shifting a small amount, the shift in position propagating down the conductor at about the speed of light. When this shift in positions gets to the other end of the conductor, under certain conditions, an electron will be pushed out.

Thats brilliant man, You finally gave me something to visualise...
I imagine a baseball court, where batsmen hit and run to the first base, then second then third and finally to home...
Here batsmen won't touch each other just like electrons and when a batsman from homeplate run towards to first base, then batsman who is already in the first base automatically runs toward the second base and so forth... just like electron-electron repulsion, batsmen repel each other...

Is this analogy okay ? or am i still lacking something?

 

[sophiecentaur]

If you want to pursue this model you might consider what happens as a result of an electron being extracted from one end of the wire. There is a surplus of positive charge in the wire (one more proton) and that will attract an electron to flow into the wire at the other end. You should really take the protons into account, too; there are just as many of them and they have the same magnitude of charge.

 

[DarioC]

RA,
Thanks, it has been an rewarding and informative process to work through for me.

Just a quick comment here on something that I noted as deleted in the last post, been a long day here so will be a short one.

I have to work on the function/concept of "free" electrons vs valence electrons in conductors. Seems there is some ambiguity about it, at least the way I am reading it.

My physics book has some good stuff about charges on capacitors, but it may take a little deeper digging than that.

More later,
DC

 

[DarioC]

And now the rest of the story:

Using a standard capacitor setup with two metal "plates" separated by a layer of insulating dielectric and connecting a DC voltage source to the plates as in standard connection with one plate to the positive potential and one to the negative, what will actually occur on the plate with the positive connection?

The majority of the information that I have seen is that the "free" electrons in conducting material, like copper, are actually "loose" valence electrons that circulate between atoms. That is to say that there are no "extra" electrons in conductive metal while in a normal uncharged state.

That implies to me that putting a positive charge on a conductive plate requires the removal of valence electrons from the atoms in that material which implies that a number of atoms of that plate, equal to the coulomb electron equivalent number, become positive ions.

Is this a correct picture? Are some of the atoms ionized? If not, what does happen?

DC

 

[sophiecentaur]

To get a better picture of what goes on during conduction in a metal you need to think of the actual structure. Amazingly, they don't talk a lot about metallic bonding in School Chemistry. This is a bit daft as the majority of elements are metals! Anyway, the basic structure of metals is a matrix of 'positive ion cores' (all the metal atoms have an electron missing) in a 'sea' of dissociated electrons that don't each belong to any individual metal atom. Each electron is attracting the ion cores nearby (and likewise for the ion cores and the nearby electrons), holding the solid together in a flexible way. It accounts for the physical properties of (pure) metals - they can flow, bend and be hammered without any of the bonds actually letting go - just re-bonding to a different group of ions. At room temperature, the dissociated electrons are in constant movement and can 'conduct electricity' as they can flow in one end and others can flow out of the other end. They also move freely through the lattice, carrying KE to lower temperature regions (good thermal conductivity). The RMS speed of electrons is very high but the mean velocity (in one direction) when conducting current is very slow. As they move through, there is a certain amount of energy transfer between the electrons and the lattice. (It's not just 'bumping into the atoms' as they say at School) This energy transfer is attributed to Resistance and the Potential Difference across the conductor tells you the Energy transferred per Coulomb of net charge flow.

 

[DarioC]

Nicely put. I particularly like the implications of the part about electrical resistance. Clarified and firmed up my view on lattice structure also.
Thanks for taking the time to explain.
DC

 

[sophiecentaur]

Cheers DarioC
I am drawn to this stuff like a bull to a red rag. People seem to refuse to acknowledge that this is all a lot too hard for a simple pictorial model to tell you 'exactly' anything much about Electricity.

 

[DarioC]

The electrical calculations of everyday electronics work are pretty straight-forward, with some exceptions, but when you start talking about the down-to-details physics of the basics that changes.

Reminds me of erbium-doped-fiber-optic amplifiers. As long as you are just coupling and fusing them together things are pretty simple, but as soon as you go just beneath the surface it is heavy-duty Quantum city.

Well it has been fun and informative. I'll be lurking here somewhere.

Later,

DC

 

[watcher]

I don't quite understand this concept, i know that electricity is the motion of electrons through a conductor.

electrons move up and down their orbital energy states (scalar motion). not thru the conductor. what moves thru the conductor is the energy.

what exactly is the potential difference between two points in a conductor?

if you imagine electrons in a magnet as tiny gyroscopes that are all spinning in the same direction, then wrap a copper wire around it, a potential is generated. right? it simply means that the electrons in the wire will be forced to align and spin the same with the electrons in the magnets. two spinning gyroscopes will tend to repel one another. this repulsive "umph" present in the conductor is what create the charge (positive negative polarization) and when the wire is closed, an energy exchange will ensue.

Is it similar to the Bernoulli's principle where the air flows from high pressure to low pressure area?

a better analogy is not air flow or water flow but wave flow. the water waves does not travel horizontally. they just go up and down in sequence so as to create an illusion that the water travels horizontally. what travels in lateral direction is the energy of the waves. thus waves and the "medium" facilitates an energy exchange. say for example, the energy of an earthquake in the middle of an ocean being transferred somewhere along a distant shore/coastline as destructive tsunamis. note that the medium (water) does not have to go from the middle of the ocean to the shore.

And also why we experience shock when we are grounded(touching the floor) and not when wearing any insulator(not touching the floor)? Floor is generally an insulator right? Then How it Sucks current from the source through our body to earth?

Thanks in advanc3...

a cemented floor conducts electricity. apparently.

 

[watcher]

Er.. I don't get it.. Could you explain a little bit more?
100 volt is too low for a conductor that large, so there will be no current flow?
Then what happens if the other end(of Conductor) is connected to the other terminal of the battery?

it's short circuited.
my take is that a closed loop of relatively highly aligned electrons will resonate with one another because the energy inputed in the circuit has no where to go but to itself. . vibrating feverishly so as to generate heat and light ( energy exchange). burning and melting the wire.

 

[DarioC]

I thought this thread was, well, dead. So..Watcher, thanks for the above information. . Along those lines could you fill us in on what happens when a capacitor has a negative charge put on the plates? Or, a positive one, for that matter. I am having some difficulty visualizing a wave stored on a capacitor plate.
DC

 

[Per Oni]

electrons move up and down their orbital energy states (scalar motion). not thru the conductor.

This is wrong. Electrons most definately move through conductors.

if you imagine electrons in a magnet as tiny gyroscopes that are all spinning in the same direction, then wrap a copper wire around it, a potential is generated. right? it simply means that the electrons in the wire will be forced to align and spin the same with the electrons in the magnets. two spinning gyroscopes will tend to repel one another. this repulsive "umph" present in the conductor is what create the charge (positive negative polarization) and when the wire is closed, an energy exchange will ensue.

I've got no idea what this is all about.

a better analogy is not air flow or water flow but wave flow. the water waves does not travel horizontally. they just go up and down in sequence so as to create an illusion that the water travels horizontally. what travels in lateral direction is the energy of the waves. thus waves and the "medium" facilitates an energy exchange. say for example, the energy of an earthquake in the middle of an ocean being transferred somewhere along a distant shore/coastline as destructive tsunamis. note that the medium (water) does not have to go from the middle of the ocean to the shore.

Not much good in this either.

SC did an exelent post (as usual) earlier on. Please study that one carefully.

 

[watcher]

This is wrong. Electrons most definately move through conductors. .

of course. in an electric current, it is the charge that flows and the thinking is that since the electron is a charge carrier particle, it is the one that flows and carry the charge with it.

when scientist as charge, how do you understand it?
is coulomb a unit of force?

 

[DarioC]

Watcher,
Might I humbly suggest that you go back and read post 36 here. It took considerable research into details that no one uses in everyday electronics, analyzed against 50 plus years of experience in electronics to come up with the results summarized there, and no one here has said that the information is incorrect.

As for coulomb it is a unit of charge, more precisely, X number of electrons. It is also one definition of an Ampere when that number of electrons "pass" by a location in a conductor in one second.

Your phrase "when scientist as charge..." is one I must admit to not understanding.

DC

 

[watcher]

I thought this thread was, well, dead. So..Watcher, thanks for the above information. . Along those lines could you fill us in on what happens when a capacitor has a negative charge put on the plates? Or, a positive one, for that matter. I am having some difficulty visualizing a wave stored on a capacitor plate.
DC

the atoms in negative capacitor plates does not have a surplus of electrons and the atoms in the positive plates have a deficiency of electrons is questionable. although this may be the normal thinking if one believes that electrons are forced to flow from one end of the wire to the other.

per oni's analogy is spot on. although this electron's flow analogy of Newton's pendulum balls was hardly be called a flow in a classical sense. it is obvious that what is being TRANSMITTED between the balls is energy.

it is is well known that the source of magnetic force is two electrons with the same spin stack on top over the other. so a magnet is nothing more than collection of electrons spinning in one direction. the effects of this alignment on copper wires is in turn aligned the copper electrons perpendicular to the magnet's electrons. this arrangement harness the innate repulsive force between electrons and an electrical force is build up between them.

so imo, a capacitor in just two plates whose one plate has an highly organized electron movement where the repulsive force between electrons are unified while the other plate is in chaotic motion where the repulsive force between electrons are just canceled out.

 

[DarioC]

Okay, Watcher, for starters:

"if you imagine electrons in a magnet as tiny gyroscopes that are all spinning in the same direction, then wrap a copper wire around it, a potential is generated."

No.

A wire wrapped around a magnet WILL NOT generate a potential difference, voltage, energy flow, whatever. MOVEMENT of the magnet or conductor relative to each other is required to induce a potential difference in the conductor.

A magnet/conductor combination will not produce a sustained direct current. It will eventually always produce a alternating potential/current. Mostly here we are talking about the most simple, bottom of the line electricity; like the voltage produced by a chemical battery. Maybe we should leave the magnets out of the discussion?

In one reply you admit that electron flow happens in conductors and then you turn around and dismiss the movement of electrons as existing in electrical theory. Strange.

DC

 

[Per Oni]

Hi watcher.

On the one hand no-one here wants to dampen your enthusiasm for physics but on the other hand you cannot just say: “imo this and that” without you giving us some relevant official websites supporting your ideas.

In a basic theory of electrical conduction I have never seen an explanation using electron spin, also your explanation of the capacitor is highly suspect. You will not get your grade (any grade) if you just go off on a tangent on your own. Perhaps after a long long time of doing your own thing will make you the new Einstein, but the chances are slim. One other thing is that using “imo” without references will get this thread closed pretty soon.

Just for the hell of it google “electron tube” (diode or triode) and see whether it changes your ideas of how current and energy flows. Best of luck.

 

[DarioC]

Oni, excellent idea on the electron tube. I was considering that for later. You have the correct approach of helping Watcher in your post, more so than mine I am embarrassed to admit.
DC

 

[Per Oni]

Hi DarioC.

Some time ago I had a discussion here about electrical currents and the flow of energy, and the end result (at least for me) was that there’s no way that electrical power is transported in a kind of mechanical way, be it hydraulic, a chain, Newton’s cradle, etc. The only analogy you can make is to compare electrical field with a gravitational field.

Using simple calculations the same as you did earlier on, when calculating drift speed etc. (post 26) you can prove that any other mechanical analogy falls flat. For example: calculate the force needed in a wire, to drive a 50 kW heater powered by a 10kV supply, using the correct gauge wire and the correct current density. Then work out the pressure generated.

The crucial question for me remains: how does the power get to its load. Suggestions are via the Poynting vector. This might perhaps work for ac but does the Poynting vector theory also include dc? I don’t know. I’m not sure about using Poynting to transport power this way. One thing is sure for me it’s all somehow in the em fields.

Best of luck with your search.
By the way I’m not always this patient, it all depends on how much time I’ve got.

 

[DarioC]

Oni, not to deflect the thread, but when I was considering mentioning a cathode ray tube to Watcher I got off on a train of thought: How to make a single electron-at-a-time source.

Then I went to this question: are there any basic particles that do not have a charge associated with them? Up comes a neutron, but that brings up that a neutron will disintegrate into an electron and a proton in a very short while when separated from an atom.

Considering that might there be some sort of charge field around a neutron that is not normally detectable?

Could any of the above be involved in slit deflection/interference of particles?

Then came up the significance of the above thoughts on inter-atom binding forces.

The places a wandering mind will go. Chuckle. (as in LOL)

I will have to ask for some good sources from the guys here for further research on these subjects.

DC

P.S. As to your comment on transferring power; doesn't it require energy and therefore transfer of power to shift an electron from one atom's orbit to the other's? If those shifts are organized into one "direction" then the power would be transferred in that direction.

I can envision some similarity to the thermal functioning of the conductor atomic lattice but, as always, I am going to have to do more research on the details of that too.

 

[Per Oni]

The places a wandering mind will go. Chuckle. (as in LOL)

Yeah that’s true. But that’s not the place where mine goes. But hey fortunately were all different. However I stick to “normal” electrons for conduction. That’s no issue for me.

 

[Per Oni]

P.S. As to your comment on transferring power; doesn't it require energy and therefore transfer of power to shift an electron from one atom's orbit to the other's? If those shifts are organized into one "direction" then the power would be transferred in that direction.

Yes that is correct, but that applies to one electron locally. The question I’m asking is: is this electron being pushed in a hydraulic way? My answer is: no they are transported in a way similar as raindrops in a gravitational field.

 

[DarioC]

No need for hydraulic, just electrostatic.

There is both push and pull. In a DC circuit the excessive number of electrons on the negative plate are all pushing against each other's static fields. The positive plate has a massive shortage of electrons and the unbalanced protons in the atoms will attract any available (as from a conductor) electrons. The repulsion and attraction (to ions) of the electric fields of each electron do it all.

The pulses that we see along a conductor(such as on initial connection) are just a localized area where the electrons are compressed together that moves along a conductor at approximately V=c.

DC

.

 

[watcher]

No need for hydraulic, just electrostatic.

There is both push and pull. In a DC circuit the excessive number of electrons on the negative plate are all pushing against each other's static fields. The positive plate has a massive shortage of electrons and the unbalanced protons in the atoms will attract any available (as from a conductor) electrons. The repulsion and attraction (to ions) of the electric fields of each electron do it all.

The pulses that we see along a conductor(such as on initial connection) are just a localized area where the electrons are compressed together that moves along a conductor at approximately V=c.

DC

.

yes. the free electron model

 

[Per Oni]

Am going away for a couple of days and therefore can't reply with any kind of proper answer, not ignoring you.

 

[Per Oni]

No need for hydraulic, just electrostatic.

There is both push and pull. In a DC circuit the excessive number of electrons on the negative plate are all pushing against each other's static fields. The positive plate has a massive shortage of electrons and the unbalanced protons in the atoms will attract any available (as from a conductor) electrons. The repulsion and attraction (to ions) of the electric fields of each electron do it all.

The pulses that we see along a conductor(such as on initial connection) are just a localized area where the electrons are compressed together that moves along a conductor at approximately V=c.

DC

.

@ DarioC, in the hope you’r still about: Even though you call it electrostatic, when you say there’s both push and pull you are still referring to a hydraulic / mechanical system. Mechanical systems push and pull direct on adjacent neighbours. The problem with this kind of power transport are the huge forces which are involved.

The way I see it is different in that an electric field does the pushing and pulling on each charge.

Now you’r probably going to say: the power supply provides the electrical field. Which is true but an electrical field is conservative and therefore needs to be replenished all the time. So in my case, we must therefore have a traveling electrical field which has to carry the power to a far way load. This must be the case for dc as well as ac.

I hope I do make some sort of sense.

 

[sophiecentaur]

I worry that people don't seem to be drawing a distinction between Field and Potential. It is Potential that is important to consider here. The field varies around the circuit, according to the rate of power dissipation in each part so it would be meaningless to say you have 230V across your supply wires and they are separated by 0.01m so the field is 23000V/m. The potential is 230V and that's what counts.

Any arm waving explanation still needs to keep both feet on the ground of basic theory if it is to work.

 

[DarioC]

Oni,
Do you propose that there is some electric "field" that is somehow not the same as the charges surrounding the individual electrons, and that it travels through the conductor independent of what the electrons are doing? Do I have that correct?

Do you mean there is a charge, field, or potential in an electric circuit that is not caused by the electrons in the conducting material?

DC

EDIT: Ah, I just had a flash of possible comprehension. Are you thinking of a electric field like that associated with a electromagnetic wave moving through "space"?

To my knowledge there is no (electric) field, charge, or potential, independent of that surrounding electrons, present or required in conductive material for the functioning of a basic D.C circuit.

.

 

[Per Oni]

Oni,
Do you propose that there is some electric "field" that is somehow not the same as the charges surrounding the individual electrons, and that it travels through the conductor independent of what the electrons are doing? Do I have that correct?

Do you mean there is a charge, field, or potential in an electric circuit that is not caused by the electrons in the conducting material?.

No this electrical field cannot be seen as independent of the free charges, ie in your example the electrons. That condition must be true as can be seen when we insert (say) a capacitor in the circuit.

EDIT: Ah, I just had a flash of possible comprehension. Are you thinking of a electric field like that associated with a electromagnetic wave moving through "space"?

To my knowledge there is no (electric) field, charge, potential, or current, independent of that surrounding electrons, present in conductive material.

To these questions: I cannot take you any further, although you can google the Poynting vector. Professor Feynman once famously said: "Intuition would seem to tell us that the electrons get their energy from being pushed along the wire……but theory says that the electrons are really being pushed by an electric field, which has come from charges very far away….."

 

[DarioC]

Gee, I thought that was exactly what I was saying. Except that you seem to think there is some EXTRA field and I am saying that the only "fields" there are the ones associated with the electrons themselves. That is all it takes. Again I am talking about a D.C. Circuit.

Feynman is exactly right, of course, but the energy is propagated by the fields of the charges on the electrons themselves, not some extra other "field." The "far away" charge is the massive collection of electrons on the negative plate of the battery.

When you go to other circuits, using varying magnetic fields, as in a generator, this situation is no longer true.

 

[Pythagorean]

Yup, even in a capacitor, the fields come from charges built up on the plates.

 

[sophiecentaur]

Yes that is correct, but that applies to one electron locally. The question I’m asking is: is this electron being pushed in a hydraulic way? My answer is: no they are transported in a way similar as raindrops in a gravitational field.

Remember that, if you want to visualise it this way, it is also being 'Pulled' at the other end of the circuit. At the same time, the positive ion cores of the metal are being pushed and pulled the other way (although they don't move) so the net 'force' on the conductor is zero.

I have a thought experiment in which a shallow tray of mercury has a voltage applied between two opposite sides. Although probably not measurable, the atoms (minus an electron) should move slightly to the negative side, causing the liquid surface to be tilted slightly, whilst electrons move steadily to the positive side.

 

[DarioC]

How interesting SC that I was just now at the library reading a Scientific American article on a new experiment using dual interferometers to see if there is a digital nature to space at the Planck size. The experimenters judge the variations will take place at MHz rates so they will be able to discern them from background low frequency shaking.

Wonder if an interferometer could be used on one end of your tray to see if the level of the mercury goes down when the voltage is applied? That doesn't even sound like an expensive experimental setup? Ah, same problem though with "geologic" shaking.

DC

 

[sophiecentaur]

Interferometry is good at spotting small displacements so I guess it would work.
The force on the mercury would be small as the field would be small. I haven't though of the details but a trough of mercury (resistivity about 10^-6) 100mm long by 10mm wide by 1mm deep would have a resistance of 0.1Ω. With 10A passing, there would be a 1V drop across it - giving an E field of 10V/m. So there would be two forces acting - mg downwards and qE sideways. Where q would be some value of effective positive charge, distributed amongst the mercury and m would be the mass of the mercury. I'm not sure what value of q would apply here but the two forces should give you an idea of the relative gravitational and electric forces - hence the slope of the liquid. Perhaps you could treat each atom separately? I started a fag-packet calculation but I got number overload and I have jobs to do!
Perhaps this needs a new thread. - will do when the mood takes me.