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I bought 1000 meters of wire to settle a physics debate [video]

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Re: I bought 1000 meters of wire to settle a physics debate [video]

#221

Post by jacquesm »

dkbrk wrote: post #203
jacquesm wrote: post #189

Earlier quoted context omitted.

> PCB layout with an emphasis on signal integrity etc would make an excellent undergrad course in school. This is strongly frequency and wave-form dependent. Just the difference between square waves and sine waves and say a few KHz to a few 10's of MHz can have dramatic consequences on how hard it will be to get a circuit to behave in the way you intended it to. I think one of the bigger insights you can have when de…

I think it was in one of Rick Hartley's videos that he talked about designing for analog vs digital. There are a bunch of points I remember, in no particular order: - the frequency of your circuit, that you need to design for, is determined by the rise and fall time of your ICs, not your clock. (With your square wave, for example, it's impossible for it to actually be square; it has some finite rise and fall time tha…

Good stuff this.

Re: I bought 1000 meters of wire to settle a physics debate [video]

#222

Post by pelorat »

griffinheart wrote: post #204
Jabbles wrote: post #201

Earlier quoted context omitted.

Calculate the volume of wire that would contain 6e18 free electrons, assuming 1 electron per atom. You can intuit it by knowing Avogadro's constant is 6e23. So 1e-5 mol, 1 mol of (atomic) Copper is 63g, so that's 6e-4g of copper. Density of copper is 9g/cm3 so let's say 1e-4 cm3 = 1e-1 mm3 = 0.1 cubic mm of copper. So one amp in a copper wire is equivalent to 0.1 cubic mm of that wire's electrons flowing out each sec…

Thank you, that puts it in perspective. Just to validate then, these barely moving electrons will create a field that induces a current on the electrons on the other side of the wire that is 1m away, which would turn on the bulb, that if the lightbulb was an ideal current detector that ignores all other sources of electric fields?

That's correct.

Re: I bought 1000 meters of wire to settle a physics debate [video]

#223

Post by BrazzVuvuzela »

ReactiveJelly wrote: post #163
phendrenad2 wrote: post #136

Earlier quoted context omitted.

This is exactly it. If being "right" or "wrong" about something involves subjective facts (is the lamp "lit" by the small amount of electricity induced by cosmic rays too?!?!) and trying to visually inspect an experiment you can't access in-person, then the only thing "wrong" is the video maker.

"Communicating badly and then acting smug when you're misunderstood" https://xkcd.com/169/

Let's not forget that Derek's PhD thesis was about the practice of making videos that dunk on unsuspecting members of the general public.

Re: I bought 1000 meters of wire to settle a physics debate [video]

#224

Post by j4yav »

gcommer wrote: post #96
tpush wrote: post #76

So, I genuinely do not get the "controversy" over the Veritasium video. AFAIU, the entire point of the video was to show that electricity travels not through wires but via electric fields ("through the air" so to speak). To illustrate this, he sets up an experiment with parameters such that the conclusion can only mean that some electricity has traveled to the bulb before any could arrive through/around the wires. He…

There's two bits of controversy: 1) Slander: He claims that the way EE is taught is a "lie" but leaves out the many ways that standard EE models agree with his result. 2) Clickbait / inadequate explanation: he leaves out many details in order to make his experiment seem far more mind-blowing that it really is.* Critique 1 can be countered by saying he is targeting a lay audience (say, they took 1 high school physics…

Is this the same channel that made that credulous self-driving car video ad for money and passed it off as an educational video? Seems so: https://news.ycombinator.com/item?id=28949327

Re: I bought 1000 meters of wire to settle a physics debate [video]

#225

Post by perlgeek »

MarkusWandel wrote: post #91

Light is slow, not exactly 1 foot per nanosecond but it's a reasonable mnemonic. Think about that, if you had an optical cable running a reasonable (these days) 40 Gbits/second link and it's 3 feet long, that's 120 bits in transit from end to end at any given moment. And that's if it is optical and ignoring the slightly slower speed of lighit in glass; any sort of actual wire is slower. For a transmission line i.e. o…

> Think about that, if you had an optical cable running a reasonable (these days) 40 Gbits/second link and it's 3 feet long, that's 120 bits in transit from end to end at any given moment. And

Since glass[1] has an refractive index of roughly 1.5, speed of light in a glass fiber is roughly 2/3 foot per nanosecond, so you actually have 180 bits in transit.

[1]: at least most kinds of glass used in optical fibers and windows, at the wavelenths typically used in optical communications, which tends to be roughly in the range of 800nm to 1500nm

Re: I bought 1000 meters of wire to settle a physics debate [video]

#227

Post by Abishek_Muthian »

tpush wrote: post #76

So, I genuinely do not get the "controversy" over the Veritasium video. AFAIU, the entire point of the video was to show that electricity travels not through wires but via electric fields ("through the air" so to speak). To illustrate this, he sets up an experiment with parameters such that the conclusion can only mean that some electricity has traveled to the bulb before any could arrive through/around the wires. He…

> AFAIU, the entire point of the video was to show that electricity travels not through wires but via electric fields ("through the air" so to speak).

Only that he doesn't context the video with that, But with a 'trick/googly' question. One of the reasonable constructive criticism I came across for this video is from Mehdi(ElectroBOOM)[1] where he explains why the real answer is not in the options offered by Derrick.

Personally I like the quality of Veritasium videos, but I lately feel that the barometer has shifted towards sensationalism rather than scientific education.

[1] https://www.youtube.com/watch?v=iph500cPK28

Re: I bought 1000 meters of wire to settle a physics debate [video]

#228

Post by Aengeuad »

Jansen312 wrote: post #85
jarenmf wrote: post #57

Earlier quoted context omitted.

That's unfortunate because his content used to be very good and this video seems only seeking engagement at a very shallow level, e.g. doesn't even mention transmission lines.

Watch his vid again. Transmission line mentioned. He even use the issue with putting cable across the ocean having issue as a possible example explain his thought experiment. Could it be you used to watch his vids in full and remember and not so much for this one?

The term 'transmission line theory' (or even 'transmission' for that matter) doesn't appear to have been mentioned in the video at all[0], and this is a complaint that was also raised by Dave Jones[1] in his critique of sorts. The video is fundamentally about transmission line problems and the term is mentioned both in the description and the word document containing further analysis, but its omission does lend some credibility to the complaints in the parent comments that the video style is intentionally pedantic (it is a pure physics vs practical electrical engineering take after all) and presented as a controversy which comes off as a bit shallow as a result.

If one were to put on a tinfoil hat it doesn't seem like much of a stretch to imagine that the plan was to have a follow up video to settle the controversy with the gist of the video being about transmission line theory and concluding with a practical demonstration of the effect.

[0] I don't have the time to carefully watch a 15 minute video to verify this, and demonstrating a lack of evidence seems difficult, but the subtitles for the video can easily be downloaded with youtube-dl and then grepped or opened with a regular text editor. Note that these subtitles are manually written and not auto-generated by youtube, and while it's possible there's some differences in the script and what is said it seems unlikely.

youtube-dl --write-sub --sub-lang en --skip-download https://www.youtube.com/watch?v=bHIhgxav9LY

grep -i 'transmission' 'The Big Misconception About Electricity-bHIhgxav9LY.en.vtt'

[1] https://youtu.be/VQsoG45Y_00?t=1013 (16:53)

Re: I bought 1000 meters of wire to settle a physics debate [video]

#229

Post by junon »

JonathonW wrote: post #66
Laremere wrote: post #25

Earlier quoted context omitted.

As much as I love Veritasium, I feel the OP video is better than his. Actually doing the experiment is really good, and it honestly feels like he was fishing for another debate like the faster than wind car by giving only a super theoretical and unintuitive explanation. (I don't have any real evidence of that, but it does /feel/ like it.) I also wonder what would happen if, instead of a setup like this: ┏───────light…

The further the battery and switch get away from the light, the less current you'll see at the battery at (sqrt(2)*width)/c s, since the electric and magnetic fields around the battery and wire will drop in strength as you move further away from them. Put another way, the main reason this effect is observable in the way shown in the video is because the light and battery, and the wires between them, are so close toge…

This makes more sense and was my first thought watching the video.

Question: At which point does the influence reach actual zero? If it doesn't, does that mean the coffee in front of me is being influenced by Jupiter, however minuscule?

Re: I bought 1000 meters of wire to settle a physics debate [video]

#230

Post by larrydag »

wodenokoto wrote: post #193
tpush wrote: post #76

So, I genuinely do not get the "controversy" over the Veritasium video. AFAIU, the entire point of the video was to show that electricity travels not through wires but via electric fields ("through the air" so to speak). To illustrate this, he sets up an experiment with parameters such that the conclusion can only mean that some electricity has traveled to the bulb before any could arrive through/around the wires. He…

My take-away from veritsiums video was: “What’s the point of the wire?” - it’s not the length of the wire, it’s the distance between power source and consume that determines how fast power travels (how does power “know” where to go, if not following the wire?) - since power travels outside the wire, it should be okay not to plug in the power consumer. I’m pretty sure that’s completely and utterly wrong, but I don’t k…

My limited understanding, according to Veritasium, is that the wire is needed to create the electro-magnetic field. Veritasium's claim is the distance of the wire is irrelevant. It's the distance between the battery (power source) and bulb (resistance) is what is relevant. AlphaPhoenix is disputing that claim saying there is a lightspeed electron "wave" through the wires.

I think this is the most fascinating debate on social media currently.

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