Thread: funky SEC splice

I guess we aren't communicating well. We seem to be agreeing about the fundamentals, and I don't understand why you think what I said ("It's not the actual movement of the electrons that makes electricity move so fast, it's their interaction.") is inconsistent. I'm addressing the question of why the velocity of electricity along a wire (nearly the velocity of light) is so much more rapid than the velocity of the electrons along it. I'm not arguing that the electrons don't move, I'm saying that the repellent force travelling ahead of their movement is what determines the velocity of electricity. Move one electron slightly, and almost instantaneously millions of other electrons down the line are also moved slightly as a result.

The tether analogy makes it sound like electrons won't be affected by a force until the tether is cut, and after that they respond only to the forces of other electrons. But the orbit of an electron is influenced not only by its associated proton, but also by the forces around it: other electrons (and protons). A better analogy is having a weak positive magnet (proton, we'll call it "P") holding a negative magnet "A" (electron) in random orbit around it (these imaginary magnets don't have poles). Bring another negative magnet, "B", near by, and the first one will be repelled in the opposite direction so that its orbit will shift, and part of its orbit will be more distant from P, where the attractive forces between the A and P are lower. Bring B closer still, and the repellent force will overcome the attraction of P, and A will slip out of orbit. Meanwhile, the change in A's orbit will already have started to influence the orbit of next pair of proton and electron through repellent force, and so on down the line. When A slips out of orbit it repels its neighboring electron out of its orbit, and takes its place.

All this happens so rapidly it's as if the electrons were actually free-flowing, but without the interaction among subatomic particles there would be no potential energy carried through the wire.

Yes, electrons are always "moving" about the nucleus of the atom, but that is like a tethered ball - it still stays with its own atom, for current to flow, the tether needs to be cut ... that now-free-electron can do some serious business.

How do you envision a free electron "doing business"? What would it do? If it were just a bunch of free electrons moving along, they would maintain an even average distance from each other, no potential electrical energy would be involved, and no electromagnetic waves created.

This nice little interactive animation shows the strength and direction of the force exerted by the proton on an electron in orbit. It takes some experimentation, but you can get one or more electrons to orbit the proton. There are other nice demonstrations on the site.

(This is a nice discussion! I'm learning as we're going along. I like that.)

Kristi,

This is what I keep going back to, unless this is no longer a valid post of yours:

Originally Posted by Kristi Silber

So you turn on the electricity at one end of a wire, and it takes time for the electrons to transmit the energy along the wire - thus there is movement of energy, even if there's no net movement of each electron.

There IS a net movement of each electron (not each and every single electron, but, as described in those links, the "free" electrons). It is that movement of each of those electrons which creates the force for the electrical current flow.

Originally Posted by Kristi Silber

The tether analogy makes it sound like electrons won't be affected by a force until the tether is cut, ...

The force that is affecting the electron on the tether is the centrifugal force that is keeping the electron circulating around at the end of the tether. The electron is circulating around the atom in a constrained motion, in one hand it is drawn toward the positive charge proton and its mass, weight, and velocity is offsetting that force, keeping the electron captive on the end of the tether - cut the tether and the electron is free to go, change the force trying to keep the electron toward the proton and the electron will either be attracted to the proton or the electron will be free to go.

I'm re-learning some things I knew many years ago when I was more into electronics, etc., than into electrical (there is a difference), and learning new things due to new concepts and technology (when I was calibrating oscilloscopes at a defense plant most were tube-type, I got to work on some of the first transistor-type oscilloscopes - much more reliable than the tube-type and need much less re-calibration (would hold their calibration longer). One of my supervisors had worked on the team at Bell Labs which invented the transistor.

This is like trying to teach an old dog new tricks, and the old dog hangs with you for a while ... then goes and lays down on the porch in the shade ... I'm going to go lay down in the shade on the porch and let the youngon work on this new trick herself.

Being a Physicist want2b, I've continued to study long after the physic classes that I've long forgotten from my college days.
I strongly suggest reading Leonard Susskind's book 'The Cosmic Landscape' to bring one up to date (if you can ignore his lack of religious convictions, I can).

Leonard is able to communicate incredibly difficult concepts in layman's terms.
The book has the first chapter dedicated to Feynman, 'The world according to Feynman'. Of particular interest to myself is the Feynman diagram pg# 39, that illustrates on a graph, the 3 dimensions of space, time, and an event and how a positron (anti-proton) and an anti-neutron go back in time, thus explaining how/why they disappear.
I would suggest first visiting pg 181. Pg 181 helps to set ones mind in the right gear, as it were. This page includes the reaction via a W-boson to emit a neutrino!

Have I pricked your curiosity? Buy this book. You can thank me later

Thanks for the recommendation, Bob. Sounds interesting. I'll have to put that on my reading list.

I'm also glad that you posted just because I've been meaning to reply to Jerry's post for ages. I started a reply then lost it somehow, and never tackled it again.

Jerry (and others), it's been a great discussion. We're getting into quantum mechanics here, pretty heady stuff by any standard. Not having thought about this in decades, it's not surprising that we sort of ran into an intellectual wall.

One thing I wanted to emphasize to any future reader of this thread is that a lot of the posts here are misinformed, mine among them. We may sometimes sound like we know what we're talking about (or maybe not!), but we're just puzzling things out. And we're definitely oversimplifying - talking about a single proton-electron pair in a copper atom, for instance, which is of course absurd.

I can't let this centrifugal force thing slide. For one thing, there is no such force as people usually envision it - like a ball on a tether. That's inertia, the tendency of an object to continue in its current direction and velocity.

An electron is like a photon, it is a particle and a wave, always moving in sort of a shell around the nucleus, kept in place by the positive charge of the proton. You can't cut that force off like you would a tether, the proton is always going to exert that force, so something else has to come along and act on the electron - another charge, heat, something - if it's going to leave the proton. (The electron actually has multiple distances it can be from the proton, different orbits associated with different energy levels. Excite the atom, and the electron gets further from the proton, then as it falls back into its original orbit it releases light.)

It's been a fun discussion!

I hear that Kristy!
Yes, it is actually centripetal force.
Wish you hadn't mentioned the various energy levels of an electron...
I've been wrestling with the question as to why there are distinct energy levels with no in between. Futile I know, as the best minds of our day are still wrestling with the question.
Perhaps I'll come up with the answer in my sleep as it seems to work better than the pea brain that accompanies me whilst awake

Right - in the tethered ball analogy, the centripetal force acts perpendicularly to the direction of the ball, with its vector toward the center post. And even when the opposite charges of the electron and proton cause the attraction, so there's force going both directions, the mass of the proton is so much greater than that of the electron that I suppose the force exerted by the electron can be ignored.

I read yesterday that the different orbits are not quite as neat and discrete as people are usually taught, though it's still helpful to think of them that way. Still, I know what you mean. Maybe I'll look into that when I have a bit of time. You've got me curious now. It's something about "packets" of energy and the wave/particle duality, I think.

Yep, It's called 'quantum jitters', like just before I do a homeowner dyi new home inspection