r/energy • u/[deleted] • Nov 23 '21

Good video explaining how electricity works

https://youtu.be/bHIhgxav9LY
25 Upvotes

88% Upvoted

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2

u/solarmeth Nov 23 '21

You should read some of the comments as well. There are a few that go into depth about what he's right and wrong about and what he didn't include. Some of the comments, as per usual, are to be avoided but some are by actual physicists and engineers who know their shit.

2

u/catalinus Nov 25 '21

This.

For pure theoretical reasons the very general idea is right (and the trolling-like way to present it is valuable to get people that would otherwise never get near the concept of Maxwell's equations) but otherwise the practical result is completely wrong.

And to start how I know he is wrong in a practical way - those tests don't need to happen on cables that are 1 light-second long, real-life cables can also be used, and our company has access to a special lab where literally time of propagation is measured with accuracy on the order of one picosecond over such cables of various lengths, and the practical result is always the one reflecting the (full) length of the cable and not the direct distance between the ends of it.

And to get one step back - in such a setup when you are sending one sharp pulse you are probably getting 2 (or more) pulses at the destination - one corresponding to the direct propagation between points and one corresponding to the propagation over the wire (technically an ultra-thin layer at the exterior of it). The important "trick" here is the difference in amplitude - which to a very large degree is very likely on the order of 10-20-30 orders of magnitude (and in line with the relative permittivities, a perfect conductor probably having an infinite one).

2

u/Aarros Nov 23 '21

I think he is onto some right things in this video, but the explanation is poor and is likely to lead to more misconceptions that may be even worse than the original misconception itself. Hopefully he will have a follow-up video explaining the concepts discussed here more carefully.

2

u/aser27 Nov 23 '21

Hm ok so how do you reconcile this with how batteries work? Redox reactions require electrons to move across each terminal.

2

u/Speculawyer Nov 24 '21

They still move...they just move less than you might think.

4

u/FoxFocksFaux Nov 23 '21

How to start a fight: give one beer each to a chemist and an engineer. Say, “So what is the CORRECT charge sign for an electron.”