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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]

#101

Post by negative_zero »

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…

I think the controversy is because that while being technically correct (bar a couple of mistakes) there are two main issues:

1) To get the result presented heavily depends on the experimental setup and this appears to be hand-waved away (or for the cynics: deliberately obscured) as it would detract from the impact of the video.

2) The definition of "ON" in the video is not what anybody would reasonably define as "ON". This is not discussed in the video therefore potentially comes of as deceptive.

As an electronic engineer I actually initially found the video confusing. I wasn't familiar with Veritasium before and I will admit my initial visceral reaction was "Oh he's just one of THOSE YouTube's and needs his clicks".

It wasn't until I went back through to understand Veritasium's unspoken assumptions, simplifications and a couple of medium mistakes that I could say: yes this is technically correct.

Personally I think with some better choice of wording the pitchforks wouldn't have come out as they have.

Edit: Added word for clarity.

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

#102

Post by userbinator »

haberman wrote: post #93
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…

If electricity doesn't travel through wires, why do resistors dissipate heat? I'm having trouble understanding what is even being claimed. Electrons are moving, without the movement of the electrons there is no electricity travel, without the wires there is no flow of electrons, so what does it mean to say that electricity doesn't travel through wires? Is the claim just that the electricity, by way of fields, travels…

Energy transfer can take place via electrons and fields. The latter has a common household example: the microwave oven.

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

#103

Post by throw0101a »

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…

> Light is slow, not exactly 1 foot per nanosecond but it's a reasonable mnemonic.

"Admiral Grace Hopper Explains the Nanosecond" is a good illustration of this (segment is only 2m):

* https://www.youtube.com/watch?v=9eyFDBPk4Yw

* https://en.wikipedia.org/wiki/Grace_Hopper

Full lecture:

* https://www.youtube.com/watch?v=ZR0ujwlvbkQ

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

#104

Post by lmilcin »

foxfluff wrote: post #90
lmilcin wrote: post #9

Fun to introduce general population to some interesting physics but please, don't call it "settling physics debate". There is NO debate. Not physics debate, not even practical debate because that knowledge is in practical everyday use. We know signals in wires take time to propagate and I have to take this into account when I design my circuits. Things like matching lengths of traces (especially differential pairs) s…

"I have never in my life length matched the two lines of a differential pair, including at 10 GHz. Never." - Rick Hartley https://youtu.be/QG0Apol-oj0?t=2765

It is right if you are only interested in making the damn thing work.

But if you don't want it to broadcast noise like crazy you want it tight and matched as much as possible.

The value of differential pair comes from the fact that they have constant common component. That only works if both components aren't shifted in time. If that happens, you will get strong common signal and say bye to nice quiet differential pair.

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

#105

Post by m348e912 »

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…

>>Light is slow

I am going to have to go ahead and disagree with you on that

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

#106

Post by jeffbee »

foxfluff wrote: post #90
lmilcin wrote: post #9

Fun to introduce general population to some interesting physics but please, don't call it "settling physics debate". There is NO debate. Not physics debate, not even practical debate because that knowledge is in practical everyday use. We know signals in wires take time to propagate and I have to take this into account when I design my circuits. Things like matching lengths of traces (especially differential pairs) s…

"I have never in my life length matched the two lines of a differential pair, including at 10 GHz. Never." - Rick Hartley https://youtu.be/QG0Apol-oj0?t=2765

I mean ... he's saying right there on the slide there's less than 1mm of length error budget at 10GHz.

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

#107

Post by AlabasterAxe »

lmilcin wrote: post #9

Fun to introduce general population to some interesting physics but please, don't call it "settling physics debate". There is NO debate. Not physics debate, not even practical debate because that knowledge is in practical everyday use. We know signals in wires take time to propagate and I have to take this into account when I design my circuits. Things like matching lengths of traces (especially differential pairs) s…

It's less "settling a debate" and more "clearing up major misconceptions than most people will come away with from watching Veritasiums video". I've taken several physics and electronics courses in my life and after watching Veritasiums video, I was under the impression that the majority of the current would be flowing through the lightbulb immediately which is not the case. So this video is just demonstrating that there's an initial "residual" current induced in the lightbulb from the electric field but the majority of the current is propagating at the speed of light through the wire.

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

#108

Post by toomuchtodo »

vmilner wrote: post #81
tgsovlerkhgsel wrote: post #70

Earlier quoted context omitted.

It may be basic, but just the _existence_ of this field wasn't something that was on my radar, let alone all the details and implications. This was certainly the most interesting and enlightening set of videos I've seen this year. I particularly like this one because "I want to get an oscilloscope and see what is actually going on" was my first thought, and this video saves me the effort of trying to set up what woul…

The history of transatlantic cable-laying is extraordinary (and didn't work for several attempts because the theory of the field around the cable wasn't properly understood).

Great book on the topic:

https://openlibrary.org/works/OL3347773W/A_Thread_Across_the...

https://smile.amazon.com/Thread-Across-Ocean-Heroic-Transatl...

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

#109

Post by userbinator »

motoxpro wrote: post #77
frosted-flakes wrote: post #48

Earlier quoted context omitted.

Especially Mark Rober. His videos aren't really about science at all, but rather attention-grabbing feats like package thief glitter bombs, squirrel mazes, and chemical volcano explosions—pure entertainment. None of his videos teach you anything like Steve Mould's videos do.

I think the point is to get people excited about science and show what is possible/spark curiosity rather than trying to recreate a classroom. You can see this by all the kids that take his classes. There is space for both to exist.

I wonder how many of those kids are going to reconsider once they find out that doing "real science" is, in reality, far more boring.

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

#110

Post by canjobear »

kongolongo wrote: post #75
jacobolus wrote: post #23

Earlier quoted context omitted.

Controversial is fine to the extent the controversy shows people struggling toward clearer understanding and better explanations, and as long as all parties are operating in good faith (i.e. not being deliberately misleading). Let me highly recommend Mehdi Sadaghdar’s (ElectroBOOM) excellent response video https://www.youtube.com/watch?v=iph500cPK28 which does a great job of empirically investigating and theoreticall…

ElectroBOOM's exchange with a retired MIT professor (it was over whether or not KVL always holds) was also very polite, respectful, and entertaining and yet surprisingly the professor who must have received and exchanged feedback before having published many, many times seemed to have a meltdown over a the disagreement.

Successful professors can get to the point where they’re no longer interacting much with people who disagree with them.
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