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Veritasium "How Electricity Actually Works"
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electrodacus:
I will try to make a resume of my demonstration that energy travels trough wires and not outside.



1) We have a capacitor on the right that is 1F and charged at 3V and one capacitor on the right also 1F but with no potential across 0V
Before the switch is closed there is a constant electric field inside the charged capacitor but there is no transfer of energy from the charged capacitor to the discharged capacitor.
By shorting the discharged capacitor at the beginning of the experiment we can ensure that there is no energy stored in that capacitor on the right and if the switch has any capacity then that switch capacity is at the same Vi potential as the capacitor on the left.

This proves that the constant electric field inside the charged capacitor can not transfer the energy to the discharged capacitor as long as the switch is open and alone should be sufficient proof that for energy to flow it requires a close loop.

2) If capacitors are 1m apart and the switch is 10m from both capacitors the time it takes from the moment the switch is closed to the moment any amount of energy is transferred to the discharged capacitor is the time it takes the electron wave to travel 10m.

This again is a proof that energy transfer from the source (charged capacitor) to the discharged capacitor travels trough wires.

3) The initial energy in this isolated system is:
0.5 * 1F * 3V2 = 4.5Ws  (I prefer Ws as opposed to Joules as a unit but they are the same thing).

With a real circuit where resistance is higher than zero the voltage after the switch was closed and circuit reached steady state will be:
0.5 * 1F * 1.5V2 = 1.125Ws  and the same amount in the other capacitor so total 2.25W

So only half of the initial energy is now found in the system the other half was dissipated as heat inside the wires and this can be verified with a thermal camera.

This is again another proof that energy has traveled inside the wire else it will not make sense to have lost half of the initial energy as heat and also see the wires heat up by the exact amount of energy missing.


I may add more points but I think this 3 points should be enough conclusive evidence that energy flows trough wires and not outside.
I'm open to any criticism just mention the point out of this 3 you do not agree with and what I did wrong.
EEVblog:

--- Quote from: electrodacus on May 05, 2022, 04:31:52 am ---2) If capacitors are 1m apart and the switch is 10m from both capacitors the time it takes from the moment the switch is closed to the moment any amount of energy is transferred to the discharged capacitor is the time it takes the electron wave to travel 10m.
This again is a proof that energy transfer from the source (charged capacitor) to the discharged capacitor travels trough wires.

--- End quote ---

If you put the switch at the end of the line then yes it will take the delay of the length of the line to start charging, exactly the same as Derek's original question would if the switch was at the end of the line. No difference at all, so that doesn't prove in any way that the energy flows inside the wire.
electrodacus:

--- Quote from: EEVblog on May 05, 2022, 08:06:18 am ---
--- Quote from: electrodacus on May 05, 2022, 04:31:52 am ---2) If capacitors are 1m apart and the switch is 10m from both capacitors the time it takes from the moment the switch is closed to the moment any amount of energy is transferred to the discharged capacitor is the time it takes the electron wave to travel 10m.
This again is a proof that energy transfer from the source (charged capacitor) to the discharged capacitor travels trough wires.

--- End quote ---

If you put the switch at the end of the line then yes it will take the delay of the length of the line to start charging, exactly the same as Derek's original question would if the switch was at the end of the line. No difference at all, so that doesn't prove in any way that the energy flows inside the wire.

--- End quote ---

Yes it proves that since energy is not flowing from the switch to the load but from the source to the load. The position of the switch should not be relevant if the energy from the charged capacitor will not need to travel trough wire.
If the switch is closer to charged capacitor / source then the wire after the switch forms another capacitor with the wire of the load thus effectively the small current Derek's is seeing is the one needed to charge that extra capacitor (the transmission line).

With the switch far away you also have a capacitor made by the transmission wires (that is fully charged before starting the test) and what the switch is doing is shorting that capacitor but from the far end of the capacitor thus electron wave that move the energy trough wires needs time to travel that distance.
 
snarkysparky:
Re Energy not transferred in the wires.

1   The light bulb will not light without the wires.  Not even with the tiniest part of wire snipped out.

2   Any material not directly touching the wires may surround the wires and not affect the light bulb function in any way.

Energy is flowing in the wires.

TimFox:
Alternative wording:  current flows through the wires into the light bulb.
The current flowing through the light bulb heats the filament to the point where it emits energy in the form of light and heat radiation.
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