Did anyone see this...

[Dr. Dickie]

Did anyone see this video.
Whereas, I understand what he is saying, I think he is wrong at the end. He seems to imply that the light will light up when the elecromagnetic waves travel from the battery to the light. I can understand that the two wires act as an antenna and so after the wave has traveled down the wire for a length less than the full 1/2 light, but he seems to imply that it just jumps from the battery to the bulb.

 

[OffGridInTheCity]

Yes, I saw it and @Vertassium is one of my favorite subscriptions
I know what you mean - He's saying the actual 'power' flows along as part of the *wave* (of something) rather than the movement of electrons. Ok, I can believe this but is the wave magnetism? or what exactly is carrying the power.

 

[Dr. Dickie]

Yes, I saw it and @Vertassium is one of my favorite subscriptions
I know what you mean - He's saying the actual 'power' flows along as part of the *wave* (of something) rather than the movement of electrons. Ok, I can believe this but is the wave magnetism? or what exactly is carrying the power.

The energy is in the form of electromagnetic energy--I have no problem with that. And the magnetic field does not get established until the electrons move (the electrons actually move very slowly--something like 15 minutes an inch--IIRC), but the electromagnetic energy from that battery is not enough to establish an electromagnetic field strong enough to jump that 1 meter gap without the wave front moving some distance along the wire (acting as an antenna and emitter).

 

[Redpacket]

At radio frequencies & even a little bit at mains AC 50/60Hz things get much more interesting. I've been in a room with fluorescent lights "on" when the light switch was off (at a radio transmitter site back in the day, not sure that'd be allowed today!.
Look up waveguides, eg in your microwave oven when energy travels along an "empty metal tube" from the magnetron to the food cavity (longer in broadcast industry applications).
At 50/60Hz, big conductors have to be rated up a bit in size because the centre carries less current than the edges - look up "surface effect" & eddy currents.
High voltage cross country power lines, eg the big 300kV etc ones, some of the energy is in the magnetic field around the actual copper wire.

At DC in our solar/battery systems, these effects are negligible. Yes the flow of current makes a magnetic field but it's (slow) movement of electrons doing the heavy lifting and requires physical metal/metal contract as we all know!

 

[italianuser]

Did anyone see this video.
Whereas, I understand what he is saying, I think he is wrong at the end. He seems to imply that the light will light up when the elecromagnetic waves travel from the battery to the light. I can understand that the two wires act as an antenna and so after the wave has traveled down the wire for a length less than the full 1/2 light, but he seems to imply that it just jumps from the battery to the bulb.

Strangely enough YouTube suggested me the video today and I watched it
It added valuable information to my knowledge, I never saw it like that.

To answer your question: it was something so new to me, and the initial imprinting in the first 10 minutes was so strong, that I didn't notice any incoherence in what he said.

 

[Redpacket]

So this guy is contradicting major physics?
EDIT: I should be saying practical engineering, physics he's quoting is OK, except Atlantic cable issue.
There's some serious misrepresentations & knowledge gaps in that video:
- "no continuous flow of electrons from a power station to your house... "
The way AC power is generated in power stations is by a rotating generator with magnetic fields in the first place.
Rotating device makes magnetic fields move through coils of wire, which makes AC current.
Yes there's transformers in between but transformers change electron movement to/from magnetic fields so you still have electrons being forced to move along cables to/from each side of a transformer.
- "why are the electrons not carrying energy back to the power station....."
They can, generators in power stations work like "motors" if they are "fed" energy. But the real point is energy (work) is put into pushing the electrons at the power station & at your place they release that energy, eg ("working") heating your radiator. So there's no energy to "go back" to the station - the station is drawing some electrons in to make up for pushing more out again in the AC mains. Bit like a water pump & a fountain, water does a loop.
- his poynting energy vector diagrams have the directions all screwed up.
Energy is not leaving the battery sideways like he claimed, fingers should wrap around battery & thumb points out of end of battery. Negative wire thumb points back to battery to make the loop not the same way as positive wire.
At low frequencies (DC & mains AC) there would be no fields without the electrons or the wires, so claiming it's "all by fields not electrons" is obviously rubbish.
EDIT: based on the discussion in the EEVBlog video below for most practical power engineering (DC & mains AC) we can ignore the field parts.
Notable exceptions to this being AC mains through the metal wall of an enclosure & high voltage power distribution lines.
- his opening question re very long loop light turn on answer is BS as well, we all know it takes a obviously noticeable time for signals eg by fibre on long distance phone calls to travel a significant distance.
EDIT: OK I'll back up on this last one also based on the discussion in the EEVBlog video below. The 1m bit is the critical bit, since we almost never build a wiring structure (in power systems) like that (a "flat sideways loop", never mind the size) it's academic.

 

[Laserlight]

I've given this some thought, to try to make sense of the physics involved. I think that I understand it. Think about conductors. There are excess free electrons available in the valence band atoms of the conductor. So essentially, there is potential electron energy along the entire conductor length. In the case of AC voltage the "localized" electrons in the conductor will respond to the oscillating electromagnetic fields and applied voltage that are induced and propagate along the wire as the AC field builds, decreases, and reverses polarity per the frequency cycle. The localized electrons in the conductor will directionally move according to the field polarity being induced into the conductor, so in reality they don't actually have to move very far along the conductor. They oscillate back and forth over some finite length during the cycle and just respond to the induced field polarity and duration. In the case of DC current the electrons do move along the length of the conductor according to the voltage applied and create a continuous directional field as long as the electrons are moving. I'm open to other opinions or corrections. I haven't broached issues like skin effect or internal wire resistance or conductor cross section as these are fairly well understood and characterized.

 

[OffGridInTheCity]

Have no idea if this is true - but here's another explanation of @Vertasium's youtube.. I totally didn't get that the wires being parallel to each other were part of the original question - and if so, then this guy suggests you can look at like a capacity situation - e.g. nothing propagates all the way along the length of the wire but rather from 1 parallel wire to the other.

View: https://youtu.be/--v5BXmFYv4

 

[jdeadman]

Have a look at Dave's video on this ge goes over the math and reasons. and how the original video is omitting some things to keep it more simple

EEVBLOG video

 

[Redpacket]

OK, agree from a physics point the first video is OK as edited in my post above above.
As the EEVBlog video points out at about the 15min mark, practical engineering for DC & AC mains mostly doesn't need to worry about the physics & fields.
Question: what happens if the wires are removed? (not talking RF stuff here, just DC or AC mains frequencies).
Answer: Disconnect the wires & nothing works, it all stops! So you need the wires as a medium for the electrons to move in, with associated fields, etc. But no electron motion = nothing happening. Electron movement + fields come as a bundle. It can't be "fields are everything", don't need electrons.

 

[Korishan]

So you need the wires as a medium for the electrons to move in, with associated fields, etc. But no electron motion = nothing happening. Electron movement + fields come as a bundle.

I kind of think of it like the electrons are "dancing" or "jiggling" in place. They aren't hopping from atom to atom to create a "flow". As they jitter back and forth, they create an electromagnetic field. When one electron jitters, it causes its neighboring electrons to jitter as well. And as they all come into synchrony, the electromagnetic field greatly increases.

Another way to think of this is envision a party boat. Then one person starts to sway back and forth. A single person doing this does nothing to the boat. However, as other people start to sway in harmony, the boat starts to move. And when everyone is swaying together, the boat will move massively from side to side.

Another example is similar to the way the "wave" works at a football game in the stadium. A few people jostle to start the way, and others start to copy it. Eventually, there's a "wave" that propagates around the stadium.

In either of these examples, if there are wires (ie people), then the wave or motion can not happen. The people aren't running around the boat or the stadium, but just oscillating in place, inducing a "push" on their neighbors.

At least this is kind of how "I" see this situation.

 

[Zwy]

I saw the video, maybe he is correct. But, what happens when charging a battery? Obviously the "electromagnetic field" in the battery isn't affected. If electrons aren't moving as he proposes, then how does a battery charge? There in lies a problem with his theory, I'd like to see his response.

 

[Oberfail]

Batteries store energy in chemical form. Its not electricity being stored, its chemicals being changed during charge, and chemicals changing their form to create electricity.
Capacitors would be interesting to know.

 

[Zwy]

Batteries are chemical energy storages. Where the electricity changes the chemicals inside the battery. During discharge, the chemistry is being changed back to the other state and is releasing energy while doing so.
Capacitors would be interesting to know.

Exactly. You agree electrons have to move during discharge and charging? That's where his theory falls apart. In order for the chemical reaction to occur, electrons have to be added or released.

Yes, capacitors also.

 

[Oberfail]

He didnt say, Electrons dont move. He said, that the elctricfield around the wire conducts the actual electrical energy.

 

[Redpacket]

He didnt say, Electrons dont move. He said, that the elctricfield around the wire conducts the actual electrical energy.

Both videos do say electrons do move, they just don't have to move far for AC or DC currents to flow. AC they move back & fwd, DC they trickle slowly in one direction.
+1 batteries it's about changing the chemistry, ie a chemical reaction stores/releases electrons.
For capacitors (two close metal/conducting surfaces with insulating layers) electrons build up on one side causing stored "charge". They are not stored in a reaction, just by being close to another conductor, similar to "static electricity".

 

[OffGridInTheCity]

I have trouble picturing the shear POWER flow + efficiency (losses) creating all these fields down the length of the wire - e.g. to heat a hot water element for example. Is the POWER moving on the electromagnetic wave around the wire?!?! Maybe what I'm missing is more accurately picturing the fields/wave... it must be a low amplitude wave? and stay within the insulation else you'd get a reaction when you grabbed a 6awg wire with 240v@50a running thru it? And wouldn't there be huge power losses with a field generated all along a 200ft wire?

Personally - I'm just not 'getting it'. Doesn't mean the math/science is wrong - just not making sense in my head.

 

[Cherry67]

Those effects Come with higher frequencies.
At 50 Hz, you have a small amount of Skin effects, means the Power / current density at the Copper surface is something Like 40% higher than in the center of the wire.
You get field effects when the wire lenght reaches a quarter of the wavelenght.....

In your sat cable, you have current on the outer surface of the inner copper wire, a few micrometer deep, and current on the inside of the outer shield.....but Most of the Power goes through the insulation between.
A yes, and on the outside, there ist no current, except you have a Bad SWR...
Yes, high frequencies are Devils Work....