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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Well i always thought that a electron traveled at the speed of light thats when i went to school .
The propagation of electrons may flow that fast, but the individual electrons themselves don't. The effect of their travel is what we consider to be instantaneous.

Picture a garden hose full of marbles, end to end, and you push a new one into one end of the hose. A marble will pop out of the other end of the hose instantly, but it won't be the one you pushed in.

It's the same with electrons. When you add an electron into one end of a conductor, it displaces one free electron of the 'first' copper molecule, which hops to the 'second' electron, and so on.

We consider electron flow to be instantaneous, but it's not quite. If you energized a 186,000-mile-long circuit, it would take about a second for the light to come on.
 

ohmhead

Senior Member
Location
ORLANDO FLA
LarryFine We consider electron flow to be instantaneous said:
Well i understand the passing of one to the next so they travel at the speed of light if they take one second to travel 186,000 miles then load effects speed.

Meaning resistance lots of it .

Just thinking a smaller wire effects the amount of current that flows.
Theory electrons this is what we learn but if one electron passing from one atom to the next atom in that wire how could distance or size effect the amount of passing when only one electron is in motion at one point in time ?

Iam thinking resistance doesnt matter but distance in time is the real effect in that wire ?
 
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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Well i understand the passing of one to the next so they travel at the speed of light if they take one second to travel 186,000 miles then load effects speed.

Meaning resistance lots of it .

Just thinking a smaller wire effects the amount of current that flows.
Theory electrons this is what we learn but if one electron passing from one atom to the next atom in that wire how could distance or size effect the amount of passing when only one electron is in motion at one point in time ?

Iam thinking resistance doesnt matter but distance in time is the real effect in that wire ?
But, there isn't only one electron in motion passing a point, unless the conductor is only one molecule thick. Many electrons flow past a single point in parallel paths. The thicker the wire, the more paths there are, and the cooler the wire stays for a given current.

I don't believe the electron flow speed is affected by resistance or reactance. Relative timing, as compared to the basic waveform, may be affected, but once the offset is established, the speed is the same. The lead or lag time remains constant from cycle to cycle.
 

cadpoint

Senior Member
Location
Durham, NC
If an element doesn't have that outer valance electron it is not a conductive material.

Maybe I should go back and study both physics and chemistry (P or C) before try answering or making another statement here, but Larry’s post # 45 got me to thinking!

What the qualifying remark in respects to both (P or C) should be is to how to address what is happening in respects to the outer valence shell electron.

As I recall the Electron is not moving physically forward it is the Charge that an Electron can hold is moving forward to the next electron, etc., etc. , is moving, as opposed to the orginal post #45:
(Keep that in mind as you re-read the following statements with my inserts)

But, there isn't only one electron (charge) in motion passing a point, unless the conductor is only one molecule thick.
Many electrons flow past a single point in parallel paths.

I don't believe the electron flow (charge) speed is affected by resistance or reactance. Relative timing, as compared to the basic waveform,
may be affected, but once the offset is established, the speed is the same. The lead or lag time remains constant from cycle to cycle.
If I’m wrong, please correct me, If I missed someone else’s same type statement, please excuse me!
 
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skeshesh

Senior Member
Location
Los Angeles, Ca
If an element doesn't have that outer valance electron it is not a conductive material.

Maybe I should go back and study both physics and chemistry (P or C) before try answering or making another statement here, but Larry?s post # 45 got me to thinking!

What the qualifying remark in respects to both (P or C) should be is to how to address what is happening in respects to the outer valence shell electron.

As I recall the Electron is not moving physically forward it is the Charge that an Electron can hold is moving forward to the next electron, etc., etc. , is moving, as opposed to the orginal post #45:
(Keep that in mind as you re-read the following statements with my inserts)


If I?m wrong, please correct me, If I missed someone else?s same type statement, please excuse me!

You're generally correct, but there's more to it than the valence shell as you also need to consider the different orbitals. In certain cases the band gap between oribtals can cause other phenomena (i.e. semiconductors, superconductors). But anyway, as far as the past few posts, I think you guys are trying to combine an understand of how an electron behaves as a particle in space with looking at a #12 wire, and all sorts of confusion results when you try to mix classical and modern physics. The impedic values do come into play as well, but only when you consider electricity as a waveform and look at a system with an electrical machine, then you end up with the whole ordeal with oscillating/damped systems, transient analysis and all that good stuff. So bottom line, I think a percise definition of electricity is difficult since the definition is tied to its physical characteristics and those traits can vary greatly depending on context and scale.
 

__dan

Senior Member
Single electron effects

Single electron effects

Single electron effects

Take the case of a hydrogen atom, which is a single proton. Modern physics teaches that the electron is a point charge at some length distant from the center, where the proton is. The electron occupies an orbit or shell.

Now the question is, does the electron "move" in its shell?

If the electron is a "point charge" and it "moves" in orbit, it must radiate energy by Maxwell's Laws, an unbalanced charge in motion radiates EM. Now, if the hydrogen atom radiates, it loses energy to its surroundings, which is a unstable condition bad enough to turn the universe into a gas cloud (no stable matter). Also, the hydrogen atom would have a magnetic "moment" where its surface has a charge difference depending on what side the electron was at that instant. This would make the hydrogen atom susceptible to manipulation in electric and magnetic fields.

But hydrogen in the un-ionized state, with a balanced bound electron, displays indefinite stability, does not radiate, is immune and impervious to surrounding EM fields, has no magnetic moment. All of the things predicted by the electron point charge model are not observed in nature.

Now, does the electron "move" in its shell? Near as I can gather, modern physics conveniently does not ask this question or test this case. MP ignores the single electron, the "Uncertainty Principle" and the mathematical description is statistical, the probability of finding the electron in a distribution. It takes a static snapshot. I found this very disappointing, a lot of time, work, and money to sit there and be BS'd. Mathematically, the electron is created by the act of observing, the cat appears in the box when it is opened but is undetermined otherwise.

In Dr Randell Mills theory above, the stable electron takes the shape of a two dimensional "great circle". A great circle is a trial mathematical solution of the electron wave equation. It can "move" without radiation in the bound state.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
I think the speed of the electrons in a wire depends on two values:

The capacitance and the inductance characteristic of the wire.


v = [1/sqrt(L*C)]


It's been a while, but I believe that equation is for the velocity of the electric (or magnetic) wave.

The electons move like marbles rolling down a board full of pegs. The start off slow and accelerate toward the speed of light. But they quickly hit a peg and bounce back, almost to the point they started. Then they start moving forward again until they hit another peg.

So although some electrons may be moving at almost the speed of light for a short time, others are moving at almost the same speed in the opposite direction. So the average speed of an electron (or the average speed of all the electrons in a particular wire) is pretty slow.

If I remember right, the "pegs" were the electric fields surrounding individual atoms.
 

skeshesh

Senior Member
Location
Los Angeles, Ca
Single electron effects

Take the case of a hydrogen atom, which is a single proton. Modern physics teaches that the electron is a point charge at some length distant from the center, where the proton is. The electron occupies an orbit or shell.

Now the question is, does the electron "move" in its shell?

If the electron is a "point charge" and it "moves" in orbit, it must radiate energy by Maxwell's Laws, an unbalanced charge in motion radiates EM. Now, if the hydrogen atom radiates, it loses energy to its surroundings, which is a unstable condition bad enough to turn the universe into a gas cloud (no stable matter). Also, the hydrogen atom would have a magnetic "moment" where its surface has a charge difference depending on what side the electron was at that instant. This would make the hydrogen atom susceptible to manipulation in electric and magnetic fields.

But hydrogen in the un-ionized state, with a balanced bound electron, displays indefinite stability, does not radiate, is immune and impervious to surrounding EM fields, has no magnetic moment. All of the things predicted by the electron point charge model are not observed in nature.

Now, does the electron "move" in its shell? Near as I can gather, modern physics conveniently does not ask this question or test this case. MP ignores the single electron, the "Uncertainty Principle" and the mathematical description is statistical, the probability of finding the electron in a distribution. It takes a static snapshot. I found this very disappointing, a lot of time, work, and money to sit there and be BS'd. Mathematically, the electron is created by the act of observing, the cat appears in the box when it is opened but is undetermined otherwise.

In Dr Randell Mills theory above, the stable electron takes the shape of a two dimensional "great circle". A great circle is a trial mathematical solution of the electron wave equation. It can "move" without radiation in the bound state.

I can't say I'm too disappointed with the results so far given the age of moden physics as well as the complexity of the subjects it deals with. The electron propogation as a function of probability rather than distance may not be exact in terms of classical physics, but it certainly is fucntional as a fuzzy-logical instrument and has been applied to communication systems, etc. As far as the cost of conducting research in such fields, you're entitled to your opinion. I mean, was it really cost effective to spend grand totals of money to supposedly put a man on the moon for no particular reason? I'd probably agree that there could be better uses for the money in helping some of the poor folks dying all around us both is the US and abroad, but since that's never going to happen I'd rather see the money go to research while it can. By the way, and I'm not sure about this since its been a while since I took modern physics, but isnt hydrogen mostly found as H2 so that the two electrons with opposite spins in the S-orbital account for there not being EM incongruity?
 

Besoeker

Senior Member
Location
UK
The general answer I thought was about a meter per second, which is getting on for four orders of magnitude different. Thats quite a large diference!

Wow.

Well, I just used basic physics.
The result wasn't a surprise. For me, it was covered in college about 40 years ago. I think it surprised our first year class then.
 

mivey

Senior Member
The general answer I thought was about a meter per second, which is getting on for four orders of magnitude different. Thats quite a large diference!

Wow.
It depends on the calculation you are referencing.

So, off the top of my head: at least wires size, frequency, wire type, and % of rated current would be considered. The idea is to calculate the number of charge carriers (mobile electrons). If you know the current, and calculate the number of free electrons available to move the current, you can find the velocity.

We know an electron has a charge of 1.6E-19 C or coulombs. We know current is measured in C/s. Let's assume the free electrons are all moving past a point at the same speed. But how many free electrons?

Copper has about 1.048772E24 free electrons per cubic inch. From this, we can find out the length (L) of a given wire that will contain one coulomb of electrons (and assume they are all used equally).

With current in I_C/s, and a wire of L_in/C, we can calculate the speed as
drift velocity = I_C/s x L_in/C = IxL_in/s

Skin effect and proximity effect are ignored for this simple calculation.

I guess you could make the velocity calculation for % loading on Al & Cu wire for the fundamental and some harmonics but I sure don't feel like it.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
It depends on the calculation you are referencing.

So, off the top of my head: at least wires size, frequency, wire type, and % of rated current would be considered. The idea is to calculate the number of charge carriers (mobile electrons). If you know the current, and calculate the number of free electrons available to move the current, you can find the velocity.

We know an electron has a charge of 1.6E-19 C or coulombs. We know current is measured in C/s. Let's assume the free electrons are all moving past a point at the same speed. But how many free electrons?

Copper has about 1.048772E24 free electrons per cubic inch. From this, we can find out the length (L) of a given wire that will contain one coulomb of electrons (and assume they are all used equally).

With current in I_C/s, and a wire of L_in/C, we can calculate the speed as
drift velocity = I_C/s x L_in/C = IxL_in/s

Skin effect and proximity effect are ignored for this simple calculation.

I guess you could make the velocity calculation for % loading on Al & Cu wire for the fundamental and some harmonics but I sure don't feel like it.

Drift velocity is completely different from the velocity of a single electron which was the original question:

Code:
Just curious how far an electron moves in one second?
I have a general answer, and it is surprising.


(Sorry Rattus, I know the origional question was really "define electricity", and we are off on a slight tangent.)

Your equation is taking the average velocity of all the electrons.

Steve
 

mivey

Senior Member
Drift velocity is completely different from the velocity of a single electron which was the original question:

Code:
Just curious how far an electron moves in one second?
I have a general answer, and it is surprising.


(Sorry Rattus, I know the origional question was really "define electricity", and we are off on a slight tangent.)

Your equation is taking the average velocity of all the electrons.

Steve
And you have a different method for isolating a single electron and finding its speed?
 

Mayimbe

Senior Member
Location
Horsham, UK
It's been a while, but I believe that equation is for the velocity of the electric (or magnetic) wave.

Well, if we think the electron as a particle that also have a wave nature, then the expression isnt that far from the truth.

I think it makes sense the expression I gave, because from what I remember the speed of light in vacuum can be expresed this way:

c = sqrt[1/sqrt(Mo*Eo)]

where
Mo = permeability of free space
Eo = electric constant

Then if we add that both inductance and capacitance are related with those constants expresed above in this way:

L -----> Magnetic fields -----> Mo
C -----> Electric fields ------> Eo

And we also add the fact that both L and C are related to the geometry of the wire (as mivey said in his post). Then we have a very good aproximation of the speed of an electron in a electric wire.
 

mivey

Senior Member
Well, if we think the electron as a particle that also have a wave nature, then the expression isnt that far from the truth.
I'm with Steve on this one.

Let's see if your premise holds water with a little experiment.

Go into your back yard and pick up the end of a straight garden hose. Using an up-and-down motion, quickly whip the hose up and down once. You should see a wave propagating down the hose across the yard.

If, at the end of this experiment, you are covered in rocks and grass from being drug across the yard as the hose in your hand raced across the yard with the wave, then I might buy into your premise.

I suspect you will end the experiment standing in your original spot with the end of the hose still in your hand.

The propagation of the wave and the travel of the particles are two different things.
 

mivey

Senior Member
But, what if a particle travels in a wave fashion?
But think about an individual particle. Why would it continually zig-zag? The shortest distance between two points is a straight line (well, kinda-sorta, but let's just use that for now). Zig-zagging is a waste of energy.

What about light traveling at the speed of...light. If it is moving in a "wave fashion", then it is moving faster than light because it also follows the extra length of the zig-zag path.

You are asking what if the particle is zipping down a winding street. Then what is the net speed toward the destination?

I'm not sure if any of this has to do with what you are after but it is fun to think about.
 
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