Mike,
carriers.
The transmitted information could be the simple fact that a ball was either pushed in at one end, or it wasn't. This **bit** of information does travel faster than the individual carriers.
At any rate, it seems you're trying to take the analogy farther than was meant. It was just suggested as a simple way to picture electrons moving in a conductor. Obviously it is not meant for any serious, quantitative study of electrical conduction.
-- Mark
I see it as a wrong approach. it has a leveling out effect. You treat smart and less smart at the same level, you alienate those who have a chance to get ahead by offering analogies everyone can understand.
carriers.
out
an
of
you
'0'.
False statement. The speed of information in your example equals the speed of the individual carriers. The input ball covers a distance d at time t with average velocity d/t. The output ball comes out at the same time t covering the same distance. The information is trasmitted at the speed of the individual balls, whatever that speed v is. As a matter of fact, every ball has the same speed while information is transmitted, assuming perfect conditions.
What you really want to say is that speed of information is independent of the lenght of the medium but depends only on the speed of the individual carrier, whether electrons or marbles. That's something totally different from what you have described but it turns out to be false also in relaticistic limits.
This is the failure of your mechanical analogy, in which there is a clear confusion between the speed of information and the speed of the carrier which is d/t. These two are always equal, in mechanical systems we can model this interaction but in electrical systems we have no idea why this holds, only hypotheses. It is sad to try to enforce at that early stage the concept that electrons are something like marbles, I was subject to the same sin when I was a student and I am against such absurdities, sorry to say.
I insist the losses are much higher than any gains when using such analogies.
Mike
-- Sounds like a great approach to me. If even the less gifted can understand the analogy that certainly shouldn\'t deter the more gifted from proceeding at their own pace, which they will. Would you advocate analogies that only the more gifted understand?
switch
Of course you are wrong and ad hominen (these two go together 100% of the time). You are making unfounded assumption, a result of your poor education and misunderstanding of the laws of physics and the foundational problems of science, I hope you do not convey that to any students.
There is no such thing as "as soon as". Every physical process exhibits a time delay depending on its dynamics. Regardless, the maximum speed of information transmission that satisfies causality is c. If you have a small mind and to you a wire looks like a 3 feet long pipe full of marbles you are a fool.
I think you are still playing marbles. Grow up and learn some games for big kids. Newton skrewed up your minds, I mean whatever was there looking like a mind.
The speed of information cannot exceed the speed of its carrier otherwise you got causality problems. You confuse this with electrons having to travel the whole wire. Obviously, you do not understand the issue being discussed.
Mike
No. The power to the lamp travels somewhat slower, in the wire, than c. Nothing, including information, can travel faster than c.
John
Mike, this isn't about modelling, it's about conveying a very basic and simple concept to people (kids) who haven't encountered it before.
If you don't give them an intuitive grasp, they may never "get it". You can't bombard them with all the gritty details right at the start, or they will throw up their hands and give up. Instead, you approach it somewhat like science itself progresses, by continually refining the details. Works for me!
I think you missed the point about information. Information in this case is the presence of "current flow". Consider the stub of pipe to be a section of wire in a larger circuit that lights a lamp. If the lamp is lit you have a binary '1' and if not it's a '0'. Once a student understands the marbles-in-the-pipe concept, s/he can understand that the speed of each electron marble is not what determines how fast the lamp comes on when you throw the switch... the information of the switch being thrown travels *way* faster than the individual carriers.
That's all, nothing deeper, no relativistic mechanics, just a single, basic, gut-level understanding that they won't forget.
Best regards,
Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis
-- I suppose your "superior" education is the reason for the missing \'an\' between \'making\' and \'unfounded\' as well as the reason why you couldn\'t grasp the reasoning behind Bob Masta\'s _excellent_ analogy.
Yes!
"Instantaneous" is sort of one of those absolute words that invites contradiction. I can't see how you'd be doing a beginner (or anybody else) a disservice to mention that the *electricity* (or the push through the marbles) travels at a finite speed, much faster than the carriers.
John
John Fields Dec 20, 12:23 pm show options
Newsgroups: sci.physics,sci.physics.cond-matter,sci.physics.electromag,sci.electronics.basics
From: John Fields - Find messages by this author Date: Mon, 20 Dec 2004 14:23:33 -0600 Local: Mon, Dec 20 2004 12:23 pm Subject: Re: Questions on electron transport in metals Reply | Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse
-- I suppose your "superior" education is the reason for the missing \'an\' between \'making\' and \'unfounded\' as well as the reason why you couldn\'t grasp the reasoning behind Bob Masta\'s _excellent_ analogy.
-- Duh. C\'mon John, do I have to include the velocity factor of the wire and account for the inductance of the filament because it\'s wound and all the rest of that crap? We\'re talkin about a switch here, and the time it takes for an electron entering the wire because the switch was closed to get to the filament VS an electron already there starting to move through the filament, and a tube with marbles in it, for goodness\' sake.
-- Fuck you. ;-) Perhaps they\'re not acceptable to _you_, but you aren\'t the be-all and end-all or the arbiter of what\'s acceptable and what isn\'t. If you don\'t like what I write and/or you don\'t like the way I choose to write, then either piss off or plonk me. Or not. It really makes very little difference to me what you think or do.
Endorsed. If it we not not so, 3.8 GHz processors would be mounted on
3.8GHz motherboards instead of 400 MHz units. Androcles.
John (applies to all of us)
Profanity and insults are not acceptable. Further, some of your remarks to me were purely argumentative. Those of us with PhDs in the sciences are expected to know these things. If you really want to split hairs, the calculations we discussed earlier are indeed estimations, as YOU should know! Now you make further attacks and accusations of others. Indeed, there IS in fact a very brief time delay from when a switch is turned on, as YOU should know, as a self proclaimed expert in the field!
I would think the goal of this newsgroup is to facilitate learning of electronics at a basic level (i.e., sci.electronics.basics) for those who are not formally educated in electronics. My training in teaching from rather prestigious institutions did not cover the use of profanity and insults as part of the teaching process and this practice was frowned upon. Those who are learning are frequently frustrated by things that they do not understand and (very often in electronics) things that do not work as anticipated.
It should be self evident that any person offering advice or teaching has an untold responsibility to accept that the person on the other end is trying to learn. With good teaching, they ultimately become good teachers. Insults and profanity are not part of that program, which is why I am politely asking you to stop.
Dominic
-- In sed, maybe. Here? nope, not unless someone wants to get into the nitty-gritty of it.
-- I don\'t see it quite like that. I believe that cause _always_ has to precede effect, but just like supersonic flight is possible, C doesn\'t necessarily have to be a limit. Cerenkov radiation is a good example of the effect of superluminal travel and, while the speed of the moving particle doesn\'t exceed C in vacuo, it does exceed C in the material in which it\'s travelling. --- >If you have an FTL transmitter of information, and the postulates of >relativity regarding light are correct, it\'s also quite easy to >construct instruments in which an event both happens and doesn\'t >happen,
No, I'm just a simple engineer; I believe what the physicists tell me. If you know of a counter-case, we'd all like to hear about it.
John
OK, I get it now, I was wasting my time talking to a crank. Bye crank.
Mike
-- Duckin\' out, Mikey? Good riddance!
switch
will
No. A TEM wave, as would be the case if the source and the lamp are connected by means of either a coaxial cable or a pair of wires forming a parallel wire transmission line, is propagated by the speed predicted byb Maxwello's equations. If the transmission line is in a vacuum, that speed would be equal to c.
Franz
switch
will
Have you ever seen a proper proof of that statement, or are you just repeating what you have been told, or have read? I ask the question quite seriously.
Franz
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