How electricity actually flows

Hope it’s OK to post a link to a youtube video here.

Interesting discussion on how electrical energy actually flows via electric and magnetic fields, not via electrons.


Well put together video, but it’s nothing new (to some). This is why you shouldn’t generally use metal sheathed cable for mains and why signal cables, in particular, rely heavily on what sheath material is used.

Yeah right, cables don’t make any difference at all.


It was new to me. Others are clearly more educated than me :slight_smile:

Totally agree regarding why cables make a difference. It’s a very complex area.


Sorry, I wasn’t being funny to you. It’s just that it’s not new information, but often forgotten. I don’t think anyone chips in with this info, so recent advice is wrong imo.

Hi Graham

Thanks for posting this.

It’s an interesting and important topic - and not just in relation to electronics.

In your note you distinguish between the EM field and electrons.

There is a paper by Art Hobson in the American Journal of Physics, ‘There are no particles, there are only fields’.

Hobson explains that electrons are field elements - i.e. they are not separate from the EM field, they are just perturbations of that field that travel through the field.

In fact, Hobson (and others) note that in QFT (Quantum Field Theory) spacetime itself (and all the things we perceive ‘in’ spacetime) is itself constituted by the EM field and the other quantum fields.



Doesn’t flow much here. Just back on after an 8 hour power cut.



Gotta love Poynting vectors - most of us found it a very trippy experience when it was taught to us in second-year undergrad EM theory. I still find it a bit weird, like it shouldn’t work but does, much like a lot of other Physics (don’t get me started on gyroscopes).

Veritasium’s videos are very good - I like the animations especially, and the link to the problems with the first submarine cables was excellent.

Cables are just bits of wire that conduct and it couldn’t be simpler? Sure thing, bub, if that’s what you want to think.



Gyroscopes? I’ve got them everywhere. Attitude Indicator, Direction Indicator and Turn Co-ordinator.

I try to keep my understanding simple and just use them.

But they are strange.

Amusing playtime. Get hold an an old PC hard drive, and power it up wth a flying lead.

Now gently move/wave it around……. You’ll feel the gyroscopic effect.

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This matches what we learned in school. Was always told that when you see electricity pylons, the energy is carried by the space between the cables, not through the cables.

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My dad used to get his students to focus on the artificial horizon on take-off and to not look out the window. The shock when they finally did after few seconds made sure that their new-found understanding of gyroscopic precession stuck with them.

I recall reading a story about a guy that would put a decent-sized gyroscope in a suitcase and then ask unsuspecting people to carry it around. When they tried to turn corners, it would act very strangely indeed.


Thanks for posting, very interesting.

I didn’t take it that way so no worries :slight_smile:

Plus I’m quite happy to admit there are gaps in my knowledge on many things that may be obvious to others!

Yes, with conventional air-driven artificial horizons, when an aircraft accelerates such as during take-off, a false nose up, right wing down ie climbing right hand turn indication, will result.

The pitch error is due to the effect of acceleration on the lateral pendulum vanes. The roll error is due to the inertia of the bottom-heavy rotor housing.

We can notice it in our training aircraft.


Thank you for sharing this. Very interesting.

I was looking for more information on this to try and work out why cables do change the sound even if most classical views are that they should not.

I also found this. Hope it doesn’t break any forum rules. A bit more Quantum theory based but helped me along. Hope it helps others too.


Why don’t you get an electric shock when you put your hand near the wire. OK I’m stupid.

Cause your hand’s made of electricity?

So, why do you get a shock when your hand does touch the bare wires ?
Or, how close can you get your hand to the wires before the “electricity” jumps the air gap. And does this depend more on the type of wire, or more on the type of air-gap ?
And what about the effect of other wires nearby, either inert, or carrying current, or nearby radio transmissions ………
Or ………
Or ……….

Interesting. Towards the end also briefly touches on purity/impurities which presumably explains why some cables are described as (for instance) 99.999% OFC.