How Wrong Is VERITASIUM? A Lamp and Power Line Story

Veritasium’s electronic question disturbed the nation! But was he wrong?

The references in the video:

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By: Mehdi Sadaghdar

0:00 Veritasium’s question and answer, was he right?
3:51 Short review of Derek’s video
5:24 Poynting Vector, direction of power flow
9:05 Detailed analysis of Derek’s question, Transmission Lines
17:37 WATCH THIS PART!

Local Forecast - Slower by Kevin MacLeod

[veritasium]

Thank you for making this video! While in hindsight I can clearly see that I should have gone into more detail with the explanation, I have really enjoyed watching all the response videos. For the record I was not suggesting the lightbulb lights at ANY current value but at some small but significant current value. I tested my LED bulb rated for 12V and found it turns on dimly when I apply 2V. There may yet be a follow up video coming. So thank you for this commentary - I'll incorporate it into any further work I do on this topic.

[ScienceAsylum]

Thanks for the shout-out, Mehdi! This was a thorough and nuanced response to Derek's video. It's important to remember that, while the energy _is_ transferred by the fields, the current is still in control. The lightbulb isn't going to do _anything_ if there isn't a current through it. During a recent live Q&A (for supporters only), I talked about Derek's question a little. My guess was that a real-life bulb wouldn't immediately turn on, but would slowly/gradually brighten over a few seconds. It sounds like you agree, which is validating.

[yumnjame]

I am truly amazed that how YouTube science community holds arguments.
Like a true gentleman, Mehdi.

[onstr]

I've begun my journey into electrical engineering as a hobby thanks to creators like you. I began watching because you were purely entertaining, and now I'm accumulating tools and measuring current and actually sat down and measured hundreds of resistors the other day and was actually excited as I thought about how it all works. I'm slowly beginning to understand more and more about how electrons move and how various components can manipulate them into doing all kinds of cool stuff. This video helped me better understand that movement. Thanks for making such great videos!

[EEVblog]

Comprehensive and briliant. Derek deserved this :-P

[darkphotons]

Finally an engineer that combines both the engineering and physic models without outright dismissing one or the other.
A very insightful video that perfectly complements Derek’s video and add some much needed realism to it.
If I could subscribe twice I would!

[rsa]

I am the Abbott you mentioned in your video. I did the initial simulations and built a scale model for verification. I loved your explanation and gained a lot more insight from the clear way you explained it. I think Derek did a great job of getting people thinking about all this, and I'm delighted you are the one who actually took the time to verify my result as I didn't think anyone looked at it! Thanks again, I just subscribed to your channel.

[ElectroBOOM]

Since youtube removed dislike count, the like/dislike ratio so far is 98.8% if anyone cares

[ElectroBOOM]

Thought to mention, even the 1 second round trip delay is not fully accurate as the LC circuit imposes its own propagation delay on top of light speed. Like I said the current flattens out traveling through the network and that slows down voltage step transitions, as you also see in the simulations at the end of video. Sorry, too much technical details!!

[Dhananjai]

This was the exact reaction I got from my father who is an electrical engineer. The point of the video was really just to show that energy doesn't just flow like water in a pipe, but the question posed in the beginning really was quite a misleading

[shanegreenup]

This is a perfect example of the value and importance of readily accessible rebuttals to all content online. Rebuttals add value to the discussion and people are better off when they get critical responses from other people who add nuance and further context to issues.

We need 'The Socratic Web'...

[FilamentFriday]

Well done. His conflicting statements drove me nuts as well.

[avir]

Dude, that whiteboard action was impressive, well done!

[JerryRigEverything]

I'm not smart enough for any of these videos.

[SagBobet]

As a complete layman and after seeing Veritasium's second video I think I finally understood the issue. You both came to the same conclusion, except that Mehdi clarified how the details of this thought experiment were important. Derek's description of electric fields is true but it is presented as if the fully complete circuit is inconsequential.

It is important that the completed circuit wires guide the electric field in order to have a light bulb fully light up, which takes a year for a lightyear-long wire. The "disconnected" parallel wires which are 1 meter apart will cause an "immediate" (1/C sec) voltage increase in the light bulb when it is connected to power, because a small amount of energy is transmitted across the 1 meter gap. However, whether the light actually turns on from this depends on the required voltage (e.g. an LED requires less than an incandescent bulb) which in the case of an LED will only dimly light up and you have to wait for the energy to be transmitted across the complete circuit before it fully lights up. Therefore, no laws of physics were broken because none of the energy was transmitted faster than the speed of light, so our conventional abstraction of how electricity "flows" still illustrates the important parts of how electricity behaves, even if it's not a complete picture. The impression I got from the first Veritasium video was that this model is completely flawed.

Did I get all that right?

[CookieQuantum]

The Veritasium video feels analogous to saying "In a hydraulic system It's the pressure waves which transmit force, not the water molecules" which is technically true but you can't have water pressure without, you know, the water molecules. Granted a hydraulic system is far less complicated than an electrical one (there's no induction for one) but I still feel that is a fair comparison.

[CrappycrapCrappy]

I just realized, these videos are the equivalent of scientists/mathematicians dueling during the olden times. Back then they used letters to communicate with each other, trying to question/disprove the other's claims, or battle it out in a good old duel. Now we are seeing it happen but 21st century style!

[Jeremy_Fielding]

I must say... well done! Very concise considering the topic. More than anything else, I am proud and excited that this level of technical discussion is happening with millions of people tuning in to watch.

[SusheelRaut]

This is one of the best videos I have watched in a very long time. As an engineer, I think, this is exactly "how" and "what" we need to teach upcoming engineers. Very well done. You have a subscriber. Thank you and keep it up.

[gavinli]

With regards to the “lies” point, I’m reminded of something my engineering professors at university would sometimes say. All models of the world and its behaviour are wrong, but some of them are still useful.