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Veritasium "How Electricity Actually Works"
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electrodacus:

--- Quote from: EEVblog on May 02, 2022, 12:31:57 pm ---I posted this comment on Derek's video, slighly expanded:

Riddle me this, a new thought experiment: Let's go extreme and say you have a 100mm diameter copper conductor at pure steady state DC delivering a small amount of power to a pure resitive load, say 1W, but go as low as you want. No transients, no skin effect, no nothing, just pure steady state DC into a resistive load.
Is there NO energy WITHIN this comicly large wire? None? It's all on the OUTSIDE of the wire in the fields at DC? Really? REALLY?

The classicial field theory math might work at DC, but I just can't get over the feeling that it doesn't pass the sniff test at DC. I don't get The Vibe I get with AC and transients. Quantum Electrodynamics and probability theory in the electron fields within the wire better passes the sniff test at DC.

Can someone please convince me that there is no energy flow within this 100mm diameter wire at all, and that all the energy flows outside the wire at DC.

--- End quote ---

In both cases DC and AC/transients all energy transfer from source to load is trough wires not outside the wires.
His test setup can be reduced to one charged capacitor (as the source instead of the battery) and one discharged capacitor (simulating the transmission line with the ends open).
Due to the fact that capacitors have an ESR half of the energy will be lost during the energy transfer from one capacitor to another and that loss will be as heat in the wires and capacitor plates that are also wires.
There is no field in the empty capacitor and the field will start to form as electrons are transferred and an imbalance of electrons is formed between the two plates.
HuronKing:
Can we lock the other thread or something? This discussion is super confusing to read when we've got entire lines of thought being double-posted in both threads. It's super confusing to follow who is responding to what.  :(

"Let's see - is this the BIG thread talking about how Veritasium is right but actually wrong or the LITTLE thread talking about how Veritasium is wrong but actually right?"  :o
rfeecs:

--- Quote from: Sredni on May 02, 2022, 03:27:30 pm ---I have a mass of 1 kg in position P at 0 meters over sea level.
I take this mass 1000 meters away to drop it from a cliff into a hole deep 10 meters.
The potential energy of the mass is converted into kinetic energy and then this is uses to generate heat.  Let's say I 'generated' 1 joule of energy.

Has this energy traveled along the 1000 meters path?


--- End quote ---

If we take the Poynting style conservation of energy argument, we know that energy is created in the volume of space around where you 'generated' it.  Energy was 'dissipated'  in the volume of space around where you dropped it.  So we can say energy flowed through the space between.  But we can't say exactly the path that the energy took.

Edit:
However, if we decide that the potential energy is located where the mass of the rock is located (like we do by saying that the fields have energy), then energy flowed along with the rock.  How much potential energy the rock contains is a problem without knowing the baseline zero potential energy of the system.

I hate analogies.  Water analogy, rock analogy, whatever.  :rant:
electrodacus:

--- Quote from: rfeecs on May 02, 2022, 05:23:18 pm ---
--- Quote from: Sredni on May 02, 2022, 03:27:30 pm ---I have a mass of 1 kg in position P at 0 meters over sea level.
I take this mass 1000 meters away to drop it from a cliff into a hole deep 10 meters.
The potential energy of the mass is converted into kinetic energy and then this is uses to generate heat.  Let's say I 'generated' 1 joule of energy.

Has this energy traveled along the 1000 meters path?


--- End quote ---

If we take the Poynting style conservation of energy argument, we know that energy is created in the volume of space around where you 'generated' it.  Energy was 'dissipated'  in the volume of space around where you dropped it.  So we can say energy flowed through the space between.  But we can't say exactly the path that the energy took.

Edit:
However, if we decide that the potential energy is located where the mass of the rock is located (like we do by saying that the fields have energy), then energy flowed along with the rock.  How much potential energy the rock contains is a problem without knowing the baseline zero potential energy of the system.

I hate analogies.  Water analogy, rock analogy, whatever.  :rant:

--- End quote ---

Yes this sort of analogies are not very useful.
Still I will try to give an answer
Before you let that mass drop there is that 1J of stored potential energy.
When you let that drop the potential energy is converted gradually in to kinetic energy (not all potential energy will end up as kinetic energy since part will be lost as heat due to friction with air).
Say 0.9J ended up as kinetic energy and if you have a perfectly non elastic collision with ground (not possible in real world) then all that kinetic energy will end up as heat (it just reminded me of a funny you tube video where someone cooked some meat using a robot hand to slap it).
If collision is elastic then not all kinetic energy will end up as heat at initial contact just a part will end up as heat the other part will be stored in compressing the mass (assuming the mass is elastic only) and then that stored energy will be converted back to kinetic energy as the mass will be accelerated back up.
In perfect elastic collision and no friction with air the mass will get back up to 1000m and since there is no loss it will be a perpetuum mobile (not possible in real life).

Yes the energy has traveled along the path. You can see with a thermal camera how jut the air that got in contact with the mass heated up and there is no heat below the mass where the mas did not get to and also no heat on the ground until the mass gets there to deliver energy same as electron needs to get there to deliver energy and electron travels trough wires thus energy is delivered trough wire.
SiliconWizard:

--- Quote from: electrodacus on May 01, 2022, 05:53:43 pm ---If "energy doesn't flow in wires" why he even needs the wires ?

--- End quote ---

Well, as I understand it, a medium is needed to hold charges, and if there are no charges, there's no field?
The question then is more about fields making charges move rather than charges moving creating fields. Or something.
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