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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]

#211

Post by y04nn »

userbinator wrote: post #126
y04nn wrote: post #112

The first signal is a close RF transmission, billions of people rely on it everyday, a current disturbs the electromagnetic field and and an antenna, sometimes thousands of kilometers away, detects a very small variation in the field (-120dbm @ 50Ω = 0.2μV). This is how our cellphones, wifi, GPS, RFID works. So, even if you disconnect the bulb and the switch you can create a current in the bulb by turning on and off…

I think the important point to note about that is it doesn't necessarily have to be a purpose-built "radio transmitter" to emit RF energy; everything which involves moving charges will radiate an EM field. This becomes especially apparent when you read the century-old books on early experiments with radio, and see the extremely crude circuitry they used to generate those waves.

Absolutely, if you turn on and off a light switch while listening an AM radio (even static) you would hear it through your speaker, as in this demonstration [1] (it worth watching the whole video if you are interested).

[1] https://youtu.be/LMxate9gegg?t=104

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

#212

Post by [deleted] »

lamontcg wrote: post #130
gcommer wrote: post #96

Earlier quoted context omitted.

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…

The problem is that his video is a mish-mash of two different concepts that were taught perfectly well in my freshman physics course. One is that the electric field travels down a wire at the speed of light while the electrons do not. The other is induced currents by moving charges. I got the answer "wrong" by watching the video because I didn't consider the tiny amount of current induced in the other wire to be suff…

[deleted]

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

#213

Post by kzrdude »

Jansen312 wrote: post #99
TempestSA wrote: post #35

Why wouldn't a simpler explanation be that the wires produce a radio/electromagnetic wave and that wave gets picked up and induces a current, which is how radio transmitters receivers work?

Most people didn't have EE education at college level. Transmission line or radio wave carrying energy is a concept usually taught much later in ones schooling. Derek basically want to target mass market that receive basic electrical knowledge that actively tells you electric "only" flows in cable. A lot of people replying to his video subsequently demonstrate that Derek is right that these group of people have the n…

He's just leaving them with a different misconception, now he's told them to ignore the wires completely. I don't think this video helped anyone (for the various reasons stated in this whole topic).

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

#214

Post by tda »

jacquesm wrote: post #188
dkbrk wrote: post #179

Earlier quoted context omitted.

> Is there really an epidemic of EE's who know how to use a field solver, but don't know to consider coupling between signal lines? Now, I'm not an EE myself, just someone who took undergraduate electrodynamics, decided to read up the subject, and found some truly excellent videos on youtube. But, at 1:00:23 in that same video I linked before ( https://youtu.be/QG0Apol-oj0?t=3623 ), Rick Hartley says this: > I spend…

EEs tend to be pretty practical in the same sense that mechanical engineers are pretty practical: they build stuff in ways that they (think they) understand to give them as good a chance as producing something that works the first time around. But the devil is in the details and mechanical engineers have one huge advantage: they deal with stuff at a scale where getting it wrong will have visible consequences. An elec…

Did you perhaps mean you changed the geometry instead of topology? Your comment got me wondering if you can change the topology without changing the schematics and I now think you can, as a schematic only defines the electrical connections and the topology is I think also the non electrical relations (what component is next to what). As far as I know topology is strictly dimensionless; size and distance are properties of the geometry. If I were not on HN I would apologise for the pedantry, but here we are

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

#215

Post by kzrdude »

blondin wrote: post #138
Jansen312 wrote: post #88

Earlier quoted context omitted.

Veritasium is the better teacher. The rest is just jumping on the bandwagon to grab viewerships. Think about it, back in your school days, you have an inspirational teacher that challenge or motivate you to pursue something. Rarely that teacher will spoonfed you with all information. I have many great teachers that explain well. But not a single one of them make it to the list of inspirational. I have 1-2 memorable t…

sorry, veritasium is not / no longer the channel you think it is. they are not out to teach first. teaching became second at some point. making views became first and more important. it is totally understandable. (they talk about the team, paying people, etc.) i personally appreciate the honesty. the video they did around the subject should still be around.

They really managed to get a success this time: lots of views for this controversial video! But for me, it feels like a lot of credibility capital was spent. I was probably part of the core audience a few years ago.

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

#216

Post by helsinkiandrew »

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…

Much of electronic engineering is built around ‘lies’ - abstractions and simplifications because that makes sense in the vast majority of cases but are ‘wrong’ at some level.

You don’t need to use Maxwells equations or the underlying semiconductor physics equations when biasing a transistor, or calculating the output of a digital XOR gate because there are abstractions that are far simpler to use and work in just about all practical situations.

And of course those abstractions break down in thought experiments and beyond their limits in the same way that Newtons laws work up to a point and then you need Einstein.

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

#217

Post by jonsen »

wtallis wrote: post #166
charcircuit wrote: post #152

Earlier quoted context omitted.

Why wouldn't the effect happen with a circle? Shouldn't the same thing happen just with more delay since they are more separated?

In the case of a circle, you should still have a radiated signal that arrives before the conducted signal. But it would be far weaker, further compounding the problems with the "light bulb illuminating" way of illustrating that a signal has arrived. In the original experimental design, it was already reckless at best to leave the viewer with the impression that the radiated signal was capable of powering the light bu…

The increased distance between the two points of measurement to be compared would also complicate matters.

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

#218

Post by jacquesm »

tda wrote: post #214
jacquesm wrote: post #188

Earlier quoted context omitted.

EEs tend to be pretty practical in the same sense that mechanical engineers are pretty practical: they build stuff in ways that they (think they) understand to give them as good a chance as producing something that works the first time around. But the devil is in the details and mechanical engineers have one huge advantage: they deal with stuff at a scale where getting it wrong will have visible consequences. An elec…

Did you perhaps mean you changed the geometry instead of topology? Your comment got me wondering if you can change the topology without changing the schematics and I now think you can, as a schematic only defines the electrical connections and the topology is I think also the non electrical relations (what component is next to what). As far as I know topology is strictly dimensionless; size and distance are propertie…

You are right, I should have used geometry.

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

#219

Post by sannee »

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…

"Friction". Mechanically, electrons in a metal conductor behave something like a glass bead in honey. Observe that the microscopic Ohm's law says that the velocity is _proportional_ to the force being applied, the electrons do not accelerate as they would in a uniform electric field in vacuum.
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