How Do Electrons Flow Through Conductive Wires?

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Discussion Overview

The discussion revolves around the flow of electrons through conductive wires, exploring concepts such as electron distribution, the impact of wire thickness, the skin effect, and the behavior of electrons in different materials. Participants also touch on related phenomena like the effects of wire curvature and the operation of Tesla coils.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that electrons flow evenly through a wire, with a question raised about whether they flow faster in the center compared to the outer regions.
  • One participant explains that in a metal, free electrons can move and that collisions with atoms lead to resistance, with the speed of electrons increasing when a voltage is applied.
  • Another participant mentions the skin effect, suggesting that electron repulsion affects electron distribution in conductors, although this is contested by others who argue that repulsion is not significant in metallic conduction.
  • A participant raises questions about the behavior of electrons in curved wires and the relationship between Tesla coils, current, and voltage, noting that Tesla coils operate at high frequencies and have high transformation ratios.
  • There is a discussion about changes in electron orbitals in wire atoms, with one participant asserting that the orbitals of the last electrons can tunnel between atoms, contributing to the conduction band.
  • Another participant questions whether a coil of iron wire has more magnetic pull than a coil of copper wire, leading to a response that suggests minimal differences in magnetic fields between the two materials.

Areas of Agreement / Disagreement

Participants express differing views on the significance of electron repulsion and the skin effect, as well as the behavior of electrons in curved wires. The discussion remains unresolved regarding the exact nature of electron flow and the comparative magnetic properties of iron and copper coils.

Contextual Notes

Some claims depend on specific conditions, such as frequency for the skin effect, and the discussion includes assumptions about electron behavior that are not universally agreed upon.

Brock
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Is is known exactly how electrons flow through wires? For example a wire is conductive, the air around it is not, and thin wires conduct worse then thick wires, would this mean that the electrons force, or flow is greatest in the centre of the wire? Like water through a pipe?
 
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Yes it is very well known. I give you a very short and simplified (but correct) explanation:

In a metal, there are so called "free electrons". There are electrons detached from the atoms (less than one for each atom) that can wander freely in the metal. But, as people in a room, they distribute more or less uniformly over al the room (metal).
All the time there are collisions between the electrons and between the electrons and the atoms. There is equilibrium in the speed of electrons and the agitation of atoms. You said that electrons and atoms are in thermal equilibrium. That is they are at the same temperature.
When you apply a voltage across the metal an electrical field appears and this electrical field pushes the electrons to the positive end. This push changes slightly the speed of electrons in the good direction. As the electrons gain speed they gain temperature and in the chocks with atoms they loss temperature and heat the atoms.
This is the resistance: the electrons lose the gained energy, giving it to the atoms. To have a current, you must provide an electric field, plus energy and this energy heats the metal.
Thin wire conduct worse than thick ones not of friction with the surface of the wire, as do water in a pipe. In a thin wire there are fewer electrons and to obtain the same current you must give them more speed. This asks for bigger electric field and gives bigger loses (heat).
 
It might also be mentioned that electrons repel each other, causing a "skin-effect" to occur with respect to electron distribution in a live conductor.
 
pallidin said:
It might also be mentioned that electrons repel each other, causing a "skin-effect" to occur with respect to electron distribution in a live conductor.

When giving an explanation it is better to avoid mentioning irrelevant subjects.
Electrons do repel each other (I said " But, as people in a room, they distribute more or less uniformly over all the room (metal).").
Anyhow, as electrons move in a sea of fixed positive charges (atoms which have lose an electron), essentially, they do not "see" the others electrons.
Then repulsion between electrons is mostly irrelevant to metallic conduction.
The "skin effect" has nothing to do with electron repulsion. It is due to magnetic forces exerted on moving electrons by the magnetic field created by the current. It is only relevant for alternating currents and at frequencies bigger than 1 or 2 tens of kilohertz.
 
Ok, so they flow through a typical wire evenly spread out, from centre to outside?

What happens when the wire is curved? Does the Tesla coil Lower amps, and raise voltage?
 
Brock said:
Ok, so they flow through a typical wire evenly spread out, from centre to outside?
Yes.

Brock said:
What happens when the wire is curved?
The current "takes the bend" and more electrons pass at the side of the wire near the center of curvature than at the opposite outer side. The dependence is of the type 1/R, where R is the radius of the trajectory.

Brock said:
Does the Tesla coil Lower amps, and raise voltage?
Tesla coil is just a transformer. But the Tesla coils that you see in labs and technical museums
work at high frequencies (20 -50 kHz), and have very high transformation ratios. They output tens of thousand of volts that are no very dangerous because of the "skin effect" at these frequencies.
 
do you know if any changes happening in the electron orbitals of the wire's atoms? does a coil of Iron wire have more magnetic pull, and eddy force then a coil of copper wire? Since if you put an iron rod in a copper coil it's more magnetic then the copper coil alone.
 
There is a "skin" effect with high frequency AC.
 
Indeed, in Chemistry and even in Physics it's well known. However, the Chemistry model in Quantum Mechanics really explains it well.

Water is an alright model to compare it to, but that breaks down real quick.
 
Last edited:
  • #10
AngeloG are you reponding to my first post, and agreeing that it flows faster in the centre of the wire? And can you explain the Chemistry model in Quantum Mechanics in more detail?
 
  • #11
Brock said:
do you know if any changes happening in the electron orbitals of the wire's atoms?.

The orbitals of last electrons "touch". In fact the orbitals do not stop abruptly but fade rapidly with distance. The consequence is that these electrons can tunnel very easily form atom to atom (and become free electrons). The energy states of these coupled orbitals degenerate and gives a very big number of states with energies distributed in a few electron-volts gap. This is what is called the "conduction band".

Brock said:
do you know if any changes happening in the electron orbitals of the wire's atoms? does a coil of Iron wire have more magnetic pull, and eddy force then a coil of copper wire? Since if you put an iron rod in a copper coil it's more magnetic then the copper coil alone.
No. Magnetic field will be almost the same (there may be a very minor and insignificant difference).
 

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