How Does Motional EMF Affect Electron Distribution in a Conductor?

[sophiecentaur]

I think, by "correct," you mean usual. Many people agree that the usual ways don't work as well as they should. Here are two interesting papers on the subject:

http://files.eric.ed.gov/fulltext/ED287730.pdf
http://www.matterandinteractions.org/Content/Articles/circuit.pdf

I had a quick read of those two papers - written by Educationists rather than Scientists, I think.
I was amused that a suggested experiment with a single filament bulb and with two in series, ignored the fact that the resistance of bulbs changes significantly with brightness (temperature). That's just the sort of howler you get when a rigorous treatment is avoided. Also, there was a really ham-fisted discussion of electrons flowing through a metal with a serious innacuracy in reasoning.
So I think that neither of those papers can be relied on to get it right in other matters.

Clearly, some change of approach is called for.

Did you mean 'your' approach or the approach of the teaching establishment?
I would always agree that improvements could be made and the pendulum seems to have swung a long way away from the rigorous approach to study. I believe there is some recent movement to a more academic system. This, I think is due to the fact that employers want to employ graduates who actually know their stuff in the hard disciplines and who can produce useful results rather than waving their arms about.
But, until they pay for a better informed and qualified class of teacher, the average standards will remain mediocre.

 

[sophiecentaur]

So it seems, then, that voltage must be (c) a measure of the relative concentration of electrons in two spots. Better?

Or Q = CV ?

 

[Jeff Rosenbury]

Your diagram lacks protons. The idea that negative charges attract positive charges is critical and lacking.

I do like your idea of redefining physics to make it easier to learn rather than be correct. Hollywood writers make far more than engineers. Clearly the value to society by physics is far less than simplicity and a good story.

[For the humor impaired: Sarcasm.]

 

[analogdesign]

So what is it? What's changed?

What's changed is the voltage, obviously.

Remember the electric field E = V/d. We didn't add or remove charge, so E is constant. We did reduce d by 1/2. Therefore V reduces by one half.

 

[sophiecentaur]

What's changed is the voltage, obviously.

Remember the electric field E = V/d. We didn't add or remove charge, so E is constant. We did reduce d by 1/2. Therefore V reduces by one half.

Please don't cloud the issue by introducing correct Science.
PS Those poor children.

 

[Gerry Rzeppa]

I do like your idea of redefining physics...

I'm not trying to redefine physics; I'm simply trying to illustrate some aspects of electronics in a manner similar to the way the operation of a vacuum tube is invariably described (ie, from an electron concentration/flow perspective).

What's changed is the voltage, obviously.

From the electron concentration and flow point of view, the change in voltage is an effect, not a cause. Bear with me...

Remember the electric field E = V/d. We didn't add or remove charge, so E is constant. We did reduce d by 1/2. Therefore V reduces by one half.

Your diagram lacks protons. The idea that negative charges attract positive charges is critical and lacking.

Yes. We need a simple way to include those aspects in our picture so that the student will be naturally led to correct intuitive inferences. I've got some things I need to attend to right now. Let me think about this a bit. I'll post a (hopefully) improved diagram later.

 

[Jeff Rosenbury]

Yes. We need a simple way to include those aspects in our picture so that the student will be naturally led to correct intuitive inferences. I've got some things I need to attend to right now. Let me think about this a bit. I'll post a (hopefully) improved diagram later.

And don't forget some moving positive charges are virtual/imaginary. For example, in P-type semiconductor material the lack of electrons moves (rather than the electrons simply moving away) even though the protons are locked in a lattice. How do we know this? The Hall effect.

I'm curious how you explain nothing as causing voltage? Me, I study a (very) little quantum theory. But explain it to a ten year old? Not without lots of loaded dice and a stacked deck of cards on hand. (Adult probability with calculus is better, but what kid knows that?)

The basic problem is that the universe is not simple. This shouldn't come as a shock to people, but apparently it does.

Instead of teaching all about electricity, how about teaching more math? Then when the child understands ratios and geometry advanced science will make more sense. But that would be hard and boring I suppose.

 

[Gerry Rzeppa]

Thank you all for your time and interest. I'm going to seek help elsewhere.

 

[davenn]

Thank you all for your time and interest. I'm going to seek help elsewhere

translated as

" I will go and find people that will agree with my misguided ideas, rather than listen to real science and learn from that"

very sad

Dave

 

[Drakkith]

I think this thread has had it. Thread locked before it degenerates into name calling and such.