Speed of Electricity

Roughly 11 to 12 inches per nanosecond is a rule of thumb I use for wire.

Electricity, in this case would be assumed to be through a wire, but it could be through air, such as lightning, which I suspect is much slower than wire?

Wire has a resistance, although feeble, and will impede the flow of electrons. Actually, electrons sort of move in a wave like motion seen at a football game in the stands. Each sort of bumps their neighbor in turn. The time it takes for a single electron to migrate this way is much slower than the 11 to 12 inches per nanosecond I quoted for the speed of electricity. So that may be why you get some answers that at the low end of the scale.

So, there are a number of ways to look at the question. Are you after signal propagation or do you want to know how long it takes a specific electron to meander its way down a wire?

If I had a 10,000km length of wire connected to a meter and turned on the switch, how long before the meter registers?

That's the sort of answer I'm after. (And the 10 year old)

The real answer is never. However, not because of propagation delays, but the resistance would be so huge over that distance that your signal will have turned into heat long before it ever had a chance to reach the end of the wire.

However, let's imagine that there are relay stations every so often along the wire and since it is imaginary, let them have a zero propagation delay for each relay station for the signal.

Depending on the wire impendence, a good rule of thumb is 85% down to 55% the speed of light for the propagation of a signal down a wire. If c is 300,000 km/s and your wire is 10,000 km, then the numbers work out to about 39 ms for the fastest to 61 ms if your propagation speed is only 55% c.

That isn't much as far as human perception goes. However, inside a high speed computer such a delay would be impossible to work with. We have some signal wires that the speed is so critical that pairs of wires and the corresponding printed circuit board traces must be matched in length so that differential signals arrive properly synchronized at the destination. We are talking about total lead length less than 12 inches where this matters (such as LVDS).

Good question!

dc travels better than ac

It is better to light a lamp than curse the darkness

Probably the most reliable figures for propogation speed (or its inverse, propogation delay) in more general kinds of conductors can be found for various types coaxial cable. Values for twisted-pair are more variable because of their comparatively higher susceptibility to the immediate electrical environment. Single conductors (return path assumed to be present but either distributed or sufficiently distant) are the most iffy. And if the single wire's electrical environment is heterogenous, so will be its propogation speed along its length. Coax avoids this environment entirely, and that's why the figures for coax are so reliable - all the action takes place between the center conductor and the surrounding shield and, electrically-speaking, the center conductor never sees the outside electrical environment.

In the late 1970s & early 80s, Control Data Corp (CDC) had their own answer to the then-fabulous Cray Supercomputer. But CDC's machine was physically much larger than a Cray, and so propogation delays (or simply 'prop' delays) were a critical issue. Prop delays in coax are a bit less than in twisted-pair, and are certainly more tightly controlled. Cray used twisted-pair (200,000 twisted-pair, all blue - or so I've been told and have seen in photographs) to connect their machine's backplanes together. To further minimize prop delays, the backplanes were arranged in a cylindrical fashion to minimize the distance between them, giving the Cray its unique 'kiosk' shape, but with seats (where the power supplies were located, making the seats nice bun warmers on those nasty winter mornings). But by using coax instead of twisted-pair, CDC put themselves on similar footing with Cray - at least in terms of prop delays - in spite of the considerable difference between the size of their machines.

--Europium

You wrote: "Actually, electrons sort of move in a wave like motion seen at a football game in the stands. Each sort of bumps their neighbor in turn. The time it takes for a single electron to migrate this way is much slower than the 11 to 12 inches per nanosecond I quoted for the speed of electricity. So that may be why you get some answers that at the low end of the scale."

Probably much lower than even the low end of the scale.

Reiterating what you said, but in a slightly different way, it is not necessary that the electrons travel from one end of the wire to the other before current flow starts. In one sense, the effect is a lot like what you'd see in a straw full of BBs: you push a BB in one end and a different BB pops out the other after an imperceptible delay. This is "current flow." In this analogy the straw, of course, is the wire. The BBs filling the straw are the conduction-band electrons from the metal itself, and inside the wire they behave collectively as a kind of "electron gas (or plasma)" filling the interstices between the metal atoms. The conduction-band electrons at the battery end of the wire "feel" the application of the electric field and nudge their neighbors in the direction of (negative) current flow, as you said, while the positions they abdicated when the switch was thrown are filled by electrons from the battery. Furthermore, the electric field itself propogates down the wire, interacting with and displacing conduction-band electrons in the wire, resulting in a redistribution of charge. The redistribution produces its own local field which, in turn, interacts with the imposed electric field in a kind of ultra-high-speed dance. Because of this effect and others (especially the wire's distributed inductance and capacitance), a rapid "step" change from zero to the applied voltage at the input end of the wire might be thought of as a kind of "shock front" which then propogates down the wire. If the wire is long enough, the leading edge of the front will tend to become "smeared" after a while.

Due to collisions with the fixed atoms of the wire (one might think of a "collision" as a metal atom momentarily capturing and then releasing the electron), a given electron's net motion in the wire can often be less than one meter per second in the direction of current flow. Nor is the motion in a straight line; rather, the electron wanders about somewhat in a "directed Brownian motion" sense - even going backward very briefly from time to time. Picture the wire as a street full of drunks, but highly-motivated drunks all with a single, definite goal! (like staying out of jail!). This is "electron flow."

Current flow, as distinct from electron flow, is much faster and is in the range posted by others on this thread.

--Europium

Electricity travels at the speed of light (it's electromagnetic radiation). That's about 12 inches per nanosecond (in a vacuum). It moves slower in metal. I use, as a rule of thumb, 6 inches per nanosecond in the metal traces on printed circuit boards. It travels at a different speed in semiconductors, like transistors. So, the speed depends entirely on the material. You can probably google an answer for a specific material.

Bhankiii writes: "Electricity travels at the speed of light (it's electromagnetic radiation)."

Well, not exactly, Bhankiii. Electricity is not electromagnetic radiation. "Electricity" involves the transport of electric charge, while EM radiation transports only energy. As electrons are the charge carriers, and because electrons have a non-zero rest mass, they cannot - absolutely cannot - travel at the speed of light for reasons best explained by The Grand Old Man of Science himself, Big Al.

--Europium

Good topic and discussion everyone-at least it's not the speed of rubber! As a child I was taught that electricity travelled at the speed of light, and of course since I was a child the speed of light as described then was corrected to its present value.

I understand that electricity tends to travel around and not through solid conductors, or at least that is what I taught later in life. I understand where this statement can be partially true. One would think that barring resistance of any type that the speed of electricity would be virtually identical to the speed of light since just as is light particle energy, electricity is particle energy.

Good topic,

Ing. Robert Forbus

You wrote: "As a child I was taught that electricity travelled at the speed of light,"

So was I, even though the facts were readily available to educators. Even just last week I discovered that my concept of convection was highly specialized and incomplete. All these years I had just assumed that the concept as taught in my 8th-grade year was a complete definition. I can still see the page in my science textbook, and I still remember being asked on the test to define Convection. Not Natural Convection. Just Convection, as if no modifier was needed. I think the schools were "dumbing-down" even then.

Fortunately I didn't have to wait as long to learn about my misconception-as-taught of electricity's speed. My best friend's dad was a ham radio operator and introduced me to the hobby. (He was therefore semi-divine in my eyes and could do no wrong.) In my sixth-grade year he gave me an old dog-eared copy of The Radio Amateur Handbook and several industrial-strength electronics texts just to keep me out of what was left of his hair. I was crazy about electronics as far back as I can remember, and apparently, I was driving him crazy too. How he put up with me I'll never know. (Sadly, the old man became a Silent Key last spring just before turning eighty. I really loved the old man, and I still have his ancient Handbook with my sixth-grader's notes and calculations scrawled in the margins. And, to my credit, I can proudly say that my penmanship has not improved one whit.)

You wrote: "I understand that electricity tends to travel around and not through solid conductors,"

Might that be Skin Effect?

--Europium

To understand how a signal propagates along a cable you need to think of it as a circuit that like this.

What you have because of the inductive and resistive characteristics along the wire with the conductive and capacitive characteristics between the conductors is a stack of band pass filters in series.

As you can see the if you insert a voltage step a one end of the wire the first capacitor will start to charge in a way controlled by the resistive and capacitive values. This will then charge the second capacitor and in turn the third and so on until the signal comes out the other end. The result is that the original step input ends up as a delayed exponential rise at the other end the shape and delay of which are dependant on the specific values of the resistors, inductors, capacitors and conductors.

You can get these values from the specifications for the cable and hence calculate what will happen to a signal.

To sum it up it depends on the characteristics of the cable and can be any where from the speed of light in a super conductor to as little as 40% of the speed of light for some really inductive cables. If you wish to go into it in detail read up on Transmission Line Theory, it goes into the analysis of the above circuit in detail.

I heard (second source) approximately 18 inches/ns, for Cu wires in Control Data Supercomputers; Seymore Cray cut the inside wire lengths to get the timing he wanted while a tech read off the wire list to him. (Unfortunately, Seymore died of severe closed-scull injuries a few years ago when an impatient Camaro driver hit and rolled his Jeep coming onto I-25 after a meeting at the Air Force Academy, in Colorado Springs, a prince of computer architecture gone, but not forgotten)

hbeecroft@gmail.com

I was a dedicated fan of Seymore Cray's ever since learning of him and his new Cray 1 Supercomputer in the mid-70s. The guy was absolutely amazing by all accounts. I had heard that he was so prolific a designer, for instance, that he often went through at least one and sometimes up to three quadrille pads a day just for his circuit drawings alone. I also remember hearing the news that he had died so pointlessly in that car accident.

Curiously, in 1999, my extremely gifted four-year-old son nearly died from exactly the same head injuries as killed Cray. But unlike Seymore, Isaac made it and today he has only minor problems resulting from what should have been, by any neurological standard in the world, an absolutely fatal head injury. The pressure from the hematoma alone was beginning to extrude his brain out through his spinal-cord opening at the base of the skull. When he arrived at the hospital's O.R., Isaac had five minutes to live, plus or minus three minutes. Nobody at the hospital expected he would make it, but if he did make it somehow, they said, the best he could hope for was to spend the rest of his life as an inert, totally mindless vegetable plugged into a life-support machine. In terms of Isaac's injuries, this outcome was considered pretty much to be wildly optimistic.

A few days after Isaac woke up, the chief neurosurgeon, who also had performed the surgery, pulled me aside and confided that until had actually seen Isaac emerge from his coma, and had heard him ask for his shoes, he had never before believed in a miracle. He was thunderstruck. And after his thirty-six years as a highly experienced and respected neurosurgeon who had pretty much seen it all, just offhand I'd say he was one guy who'd know a miracle when he saw one. Well, he finally saw one: my kid.

Too bad Seymore Cray wasn't so lucky. Our loss, as well.

--Europium

Treatment, I am told, for closed-skull trauma is to cut a section of the skull bone so the brain has space to slightly expand to relieve deadly pressure on the brain, but Seymore didn't make it to the hospital in time for this procedure. That your son lived (evidently without this procedure) is a miracle, thanks to God for His mercy, maybe your son will grow up to be another Seymore and be a great blessing to mankind like Seymore's contributions are! I'm told by someone who worked with Seymore at Cray Computer, that he would wait in line at the copy machine with the secretaries and others to run his own copies. Yes, Seymore is missed, by many. And how did we get on this subject when we were discussing the "Speed of Electricity"? Well, there is also the human aspect to us human engineers. We are humans working with parts of God's creation, and like Him, being creative too.

You wrote: "That your son lived (evidently without this procedure) is a miracle, thanks to God for His mercy, maybe your son will grow up to be another Seymore and be a great blessing to mankind like Seymore's contributions are!"

In the O.R. they opened my son's skull for this very reason, and this is what saved his life. Unlike Seymore, Isaac has little interest in computers. For him they're just a tool; a means to get what he wants.

Isaac's real interest is in History, especially Military History. For a twelve-year-old, his knowledge in this area seems almost fathomless. He drinks in knowledge like a sponge, and his capacity for learning new things seems bottomless. Ike reads anywhere from 30 to 60 books a month, and none of these books are anywhere to being even close to 'coffee-table fluff.' Hardcore History; that's what he likes. He exhausted the local library's resources in no time, and so I took him to the main library whose collection of History books kept him busy for awhile - that is, until my ex-wife, for dubious reasons known only to her, moved to another state with my boys. But that's a whole different tale.

Isaac is a very serious child, as children go - that is, until you get him on the subject of Monty Python. Even the mere mention of Monty Python brings his dimples out of hiding. Ike's favorite sketch is the "Constitutional Peasant," followed by the "Architect Sketch." He's also very fond of 'Donuts vs The Police' jokes, for some reason which I can't explain other than to say that I'm fond of making them up for him.

You wrote: "We are humans working with parts of God's creation, and like Him, being creative too."

All part of being "made in His image..."

--Europium

Glad to hear of your son's happy ending!

I could go on clinically about the event, but there is nothing more that really needs to be said. Life is a gift and you and your son are blessed with it.

Interesting topic...

I've long been aware that the speed of the current is some decent fraction of light speed while the speed of any given electron is far (far, far) slower than that.

I can see that it's fairly straightforward to measure the former, but (while all these brains are on the subject) I'd be interested to know how it's possible to measure the speed of the actual electrons. Given that any one electron is pretty much identical with any other, how can we know which one is popping out the end and how long it took to get there?

Indeed. Further, electrons have mass, so how come they can travel at speeds approaching C without the mass increasing enough, at least, to make a wire sag?

Where's Jorrie?!

Indeed. Further, electrons have mass, so how come they can travel at speeds approaching C without the mass increasing enough, at least, to make a wire sag?

It's not the electrons that are moving at close to the speed of light it is the propagation of the disturbance that is moving close to the speed of light.

Electrons are all negatively charged and so repel each other. Now imagine that I jam an extra electron in to the end of the cable. The extra electron pushes on all the electrons near it which in turn push on the next electrons along the cable and so on till an electron fall out of the other end of the cable. The original electron is still in the cable and has hardly moved at all yet the effect has resulted in another electron being expelled at the other end of the cable.

It is the propagation that moves at close to the speed of light not the electrons themselves.

So does that make the disturbance a function of 4-dimensional space-time, like gravity? If so, then why is the electrical disturbance running at sub-light speed and not like gravity which, according to Hawking and others, is instant over huge distances?

[High temperature alarm raised on Brain 0.0 subsystem at this location. Looking for an alarm accept/reset action elsewhere]

So does that make the disturbance a function of 4-dimensional space-time, like gravity? If so, then why is the electrical disturbance running at sub-light speed and not like gravity which, according to Hawking and others, is instant over huge distances?

It is a four dimensional problem, time being the fourth, but not like you think. I will give you another example that might be easier to understand.

This is about those executive toys that have the 5 steel balls suspended on strings from a frame so they can all swing. When you pick up one of the end balls and then let it go when it strikes the four stationary balls the one that was moving stops and the ball at the other end shoots of at almost the same speed. The energy that the first ball possessed is transmitted along the stationary balls without moving them perceptibly. When the energy gets to the last ball it has nowhere else to go so that balls moves.

The energy is transferred along the string of balls at great speed yet the balls themselves moved so little that you can't detect it.

This is the transmission of energy by mechanical means and the speed is controlled by the elasticity of the steel balls. With electricity the energy is transmitted by the electromagnetic force and move at a speed that is governed by factors like the capacitance, inductance, resistance and leakage of the cable.

I hoped that has helped because your brain high temperature alarm has given me a headache, so would you kindly find that acknowledge button and press it.

Hi there it's so fast, how do you measure it in your mind...?

If that's what your looking for try this. works for me.

I can travel by aeroplane from New Zealand to Greece (half way around the world)

That takes approx 13 hours (in a jumbo jet)

The circumference of the earth at the equator is 24,901.55 miles (40,075.16 kilometers) a round trip would take 26 hours in the same jet (non-stop).

[ more notes about earth - But, if you measure the earth through the poles the circumference is a bit shorter - 24,859.82 miles (40,008 km). so half ways is about 12425 miles. This the earth is a tad wider than it is tall, giving it a slight bulge at the equator. This shape is known as an ellipsoid or more properly, geoid (earth-like). ]

Internet packages (email) go about five times around the world in one second.

124299.1 miles in one second

"SheZzzz.. that's fast" but wait..? what's the hold up then..?

From versaverter

Light speed = 670616629.4 miles per hour

light speed = 670616629.4 miles per hour

jumbo jet = 623.2353059 miles per hour

1,076,025.0 times faster than a jumbo jet

electricty goes 26932 times round the earth per hour

electricty goes 7.48 times around the earth each second
and check my sums , but you'll get the idea

and the next anomaly is nautical miles.. huh?

Years ago in "Shop" class it was explained to me like this; Fill a 10' length of 1/2" pipe with marbles. As soon as you push one in, another one comes out the other end. That should be language a ten year old can understand.

OK! This whole thing has got to be so much fun; I'm going to restate the question.

If I'm standing next to the power station here in the UK and I take a 220v 60Hz feed straight from the station, and take another feed that's been taken around the country (I'm talking hypothetically here!), will the frequency's match?

What I remember of theory says it should!

So – can you get a long enough lead so that they don't?

PlbMak the answer is the frequency of the power from the lead that ran around the country compared to the one from the power station would be the same but the phase angles would not match. The ones from the lead would lag due to the propagation delay in the lead. Think about inserting a sin wave into the circuit in my earlier post and what would happen.

If you look in the diagram then the power coming from the lead would look like the three offset voltages and if you connected a meter from the lead to the power station then you would see a voltage like A, B or C.

At science classes one day they connected ten students to a telephone, one of the old ones that you had to wind up, just give it a small crank sends the last person in the chain leaping for joy ( was that painful, we'd asked him..?) obviously the Hz still had a punch at the end of the line I'm just glad I chose the mddle somewhere LOL

I'd say from memory that the volts/Hz are the same but the amps are deminished over distance, it's a guess. and yes it is fun to go over all this stuff. just like those marbles you need more push for a longer tube of them.

To>masu

oH so that's why I'm always waiting at the end of the copper cable too many collisions, well actually that was Aimes training that first mentioned 5 times round the world in a second . hahaha good ol` microsoft training huh..! go figure. no wonder it was too easy to correct the teachers in that class.

If your local power station was producing power at 60Hz it is very unlikley that it will be connected to any other power station in the UK, all our power stations generate 50Hz

Be careful upon passing Liverpool. It is said that, due to an administrative error that cannot be corrected, the phases rotate the other way compared to the rest of the country. Then, that explains a lot about Liverpool...

I'm not sure where you got the 5 times round the world in a second from, it just doesn't work like that. By the time you add up all the delays in the routing and switching you would be lucky it the message got there in a second . If a signal goes via a satellite in geosynchronous orbit you need to add 72,000Km to the path length which is about 240ms plus any delay caused by the routing and switching. Unfortunately there is no way to get round this delay if you use geostationary satellites. I worked on extended X25 packet switching networks back in the 80s and we always allowed for a 1 second for a network round trip if a packet was switched through a satellite. Iridium phones use a network of satellites in low earth orbit. They work like the cell phone network except the phones are relatively stationary and the cell nodes are all moving at 7.7Kms^-1.

(speed of light)/(nanosec)=

3x10^8(m/s)/10^-9(s)=.3m/ns (in a vaccuum)

that's the fastest, but typically electricity (DC) travels about 2/3 the theoretical limit due to lump parameters of wire.

when looking at electricity with frequency components(non-DC), their are numbers of lag and lead factors, but that really has to do with attenuation and synchronization. All non-DC electricity has frequency dependencies and can be calculated by determining the equivalent transfer function of the entire path including all resistance, reactance, and susceptance summed up in an Impedance equation. The impedance equation can be algebraically manipulated with the signal sources to yield a transfer function yielding the dependency on frequency. Basic equations can be found at http://en.wikipedia.org/wiki/Electronic_filter. Another good summary is Schaum's outline of signals and systems. Good luck.

I haven't heard the most simple answer yet, so i'll insert it here.

The speed (wave speed, like sound, not actual electrons) of electrical signals in any medium, regardless of resistance (we all know it exists, that's not what the question was asking), depends solely on IMPEDANCE.

To put it simply, considering RF (coax, with center conductor and grounded outer shell) cable as the example, wave speed (V) will be C/sqrt(K) where K is the permittivity of the insulating material between the ground and center conductor.

In an RF cable, where the insulation is designed to have a low permittivity, but keeps the center conductor still in close proximity to the shielding, it will have a higher permittivity and a SLOWER speed, dropping from C to near-C. Think of this like how you drive slower on a narrow road, but speed when there's four open lanes of highway. (Except electron waves don't have gas pedals)

If you consider a power line, which is separated by tens of feet from a relative ground source vs. a mm or two for an RF cable, the speed is much closer to the speed of light (C).

Moral of the story: The closer your conductors are together (power and ground), the slower the wave will propogate.

http://www.allaboutcircuits.com/vol_2/chpt_13/3.html

Yeah, I thought he wanted a number too. Like 300,000 km/s or something.

muiporuE--

Well, my answer was that it VARIES. For a wire that's 'out in the middle of nowhere', the electron wave will move NEAR c... so like 290,000km/s

If you talk about a pair of wires (give or take) about 1/4" apart, you're down by about a factor of 10, down to like 30,000 km/s.

I figured the understanding of the answer was more important than throwing numbers out there.

Yeah, I know, and judging from my earlier posts, I'd say that was my intent, too. My last post was really more a tongue-in-cheek poke at myself for my never having answered his question with an actual value.

--E

Clearly there isn't a figure that could be given as a 'constant', such as the speed of light is a 'constant'

This thread has given me two things, however.

1) A better way of explaining the physics to the young-un.

2) Confirmation that electrical engineers can't help but get really technical.

Thanks, PlbMak

Life... is complicated. Simple answers tend to have the drawback of being wrong in certain cases. Sorry.

You might try using water waves as way to relay the wave properties, and sound waves to relay the concept of compression wave propogation to the young'n. They tend to be very analogous to properties of electrons in wires.

I still thnk the telephone (windup type) is a short way to seeing how fast electricity goes as the last person in the chain will show.

one thing I would lke to ask is if there where more people on the chain between the sending and recieving end, does the speed of electricty passing through them increase in the relation to the number of people connected (distance)?

I learned in TV repairs that if one moves their finger away quickly from the spark left in the cathode tube, as it makes contact with earth through the body, (when the TV has not been switched off for 12 - 24 hours) the quicker one pulls their finger away the remaining spark traveling towards the finger (earth) will always catch up and the further apart you manage to get the greater the punch one gets.

does this also happen when there is a greater distance (number of human bodies in the case of the wind up phone) between the ends of the chain of people or does the spark only increase speed over distance when the spark of electricity is traveling through the air (uninpeaded by the body's frame/mass)?

mdbobbo you asked

"one thing I would lke to ask is if there where more people on the chain between the sending and recieving end, does the speed of electricty passing through them increase in the relation to the number of people connected (distance)?"

The answer is no the speed is a function of characteristics alone. Since the characteristics remain unchanged by adding further students to the chain then the speed would remain unchanged. The time taken for the impulse to travel through would however increase proportionally to the increase in distance. Think of it like the circuit in post #10, it would be like adding another set of components to the end.

As for the question about getting bitten by the HT in a TV I have also heard the story but however I am unfamiliar with the theory behind it so I can't comment. Someone else may be able to enlighten us.

The only thing I can think of is that it is an inductive discharge condition. In that case, the arc length is proportional to the intensity, keeping current constant(doing what inductors do best), but increasing the voltage. More intensity means more power which means more fried cells/nerves. Ouchers.

If it's capacitive, I have no idea.

You wrote: "If it's capacitive, I have no idea."

If it's capacitive, you may yourself begging your Inner McDonald's Associate for a second crack at that lucrative Liberal Arts degree. Caps are far less forgiving, as a rule.

-E

[quote]about getting bitten by the HT in a TV I have also heard the story [/quote]

The rule of thumb is. A. either get your finger away quick and get a big belt from the electricity or B. get your finger burnt a little more and have less pain. not much of a choice when your in that inviroment with the arc traveling to your poor finger but I have seen it done and it does make a lot of difference to the belt you'd get, just in case someone forgets to wait for 24 hours, although the power in a TV can be arced away instantly by appling a metal instrument like 2 long screw drivers from that connection on the side where the high tention lead enters the cathod tube (covered by a rubber boot seal) to the metal rim around the cathod tube it's self ( not sure abouut the new TV thought) tounch the two screw drivers together after connecting both to the various part ( very carful not to break the glass) will release the power instantly through the screw drivers. A good idea when servicing TV's at a clients address because if you'd asked them to turn the TV off for 24 hours before some of them may feel obligated to lie about how long it's been disconnected from the mains.

Also thanks for the rereference to your previous post I'm learning fast and it's also helpful to my project SPssATV so your also on the books as a contribituer to that.

I still thnk the telephone (windup type) is a short way to seeing how fast electricity goes as the last person in the chain will show.

one thing I would lke to ask is if there where more people on the chain between the sending and recieving end, does the speed of electricty passing through them increase in the relation to the number of people connected (distance)?

I forgot to comment on the telephone generator comment you made. Though I'm sure the example of the people chain will illustrate that 'electricity' travels, it's a slightly more complex answer to how fast it travels because of the composition of the body. (not to mention slightly dangerous for those with heart conditions who use both arms as their connection points, placing the signal through the chest)

To answer the question about if more people are involved, the signal does not travel any faster per person than it did before. Like mentioned before, the signals travel on the order only slightly less than the speed of light itself, so for your experiment, it would seem that 'electricity' travels almost instentaneously no matter how many people you had in the loop.

Don't forget there is a delay between when a person receives an electric shock and the muscles contracting. If it's an involuntary or direct contraction caused by the flow of electricity through the muscle then the reaction will be fairly fast but if it is a voluntary contraction then you need to allow for the reaction time of a person. Either way the biological delay is going to be massive compared to the electrical delay.

About as fast as greased lightning with a zero impedance path!

Blimey... some people really know how to complicate something.

Consider AC... the actual drift velocity of the electrons is pretty slow say walking pace...but as they are going back and forth ('cos it's AC) they don't actually travel along the wires at all .

The voltage is however transmitted 'Bloody Fast' (that should satisfy the kids) due to the electrons all exicing their neighbours.

Remember that marmalade ad' on the TV where there is a person at each end of a very long table... there is a row of marmalde jars right down the middle?
She says pass the marmalade...he shoves the end one and they go clank, clank, clank and one at the other end pops out and she grabs it.
Or another analogy ..Newton's Cradle.... the balls keep their positions but as one hits at one end, one pops off the other end.

I think you have all been very silly and should go to bed with no super... the man wants explanation for kids....

works for me

Del