161–170 of 242 posts
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>>Light is slow I am going to have to go ahead and disagree with you on that
Most stuff in the universe is moving apart faster than light, so yes it’s quite slow. ;)
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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…
What's happening is that you are straying further and further from the "impedance matched" condition (the inductance per unit length stays the same but the capacitance goes up with the separation--however, being "too close" will also cause similar behavior). Consequently, the energy transmitted per reflection gets smaller and smaller.
Part of the problem in this whole discussion is using a "light" as a "threshold detector" where the threshold is effectively microamps. A microamp threshold detector is not what people think of as a "lamp".
If the original Veritasium video had showed the current flow via meter, oscilloscope, etc. nobody would be terribly surprised as it would show small flows getting bigger upon each reflection until it built up to the full current.
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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…
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.
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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…
I still don't buy "then yes this is correct". If "ON" is defined as a state where ANY electromagnetic field flows into the lightbulb, then it is "ON" even before you throw the switch, because other photons are already shooting around all over the place, including from the neurons in your body pondering the result just before you throw the switch. The definition of "ON" is exactly the main controversy with this and no…
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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.
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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…
Why wouldn't the effect happen with a circle? Shouldn't the same thing happen just with more delay since they are more separated?
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I think the confusion is that Veratisium's original video made it seem like this was the only/main way electricity travels, whereas in reality, there's two separate ways: One of them take's 1/c and the other takes c/2. Also, what most people think of the light bulb going on in the real world would be the c/2 one, not the 1/c one.
What is c/2? 1/c was because the distance between the lightbulb and the battery was 1 meter. m / m/s = s With c as the numerator, I don't even know what the units of that 2 would be? m/s²?
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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…
I still don't buy "then yes this is correct". If "ON" is defined as a state where ANY electromagnetic field flows into the lightbulb, then it is "ON" even before you throw the switch, because other photons are already shooting around all over the place, including from the neurons in your body pondering the result just before you throw the switch. The definition of "ON" is exactly the main controversy with this and no…
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…
Now, if you follow it carefully, it makes a different point, that is actually correct: it actually claims that some energy travels this way, since the electric field is not strictly bound to the wires, some part of it radiates out.
What the video is sorely missing is a discussion of the intensity of that field, which is going to be extremely low even 1m away from the wires, for typical batteries. These effects are absolutely important though in high power cases, where even a small fraction of the energy carried along the wire leaking to nearby wires still means you can actually light a lightbulb (or burn many other things).
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…
Among EEs that I've seen there are only really three points of controversy: the "any current at all turns the bulb on" bit which he didn't mention in the initial pre-video quiz (but which is super important), that he missed the unit of meters in the `1/c seconds` answer (it should be `1m/c seconds`), and (for the pedants & puzzle solvers) that he ignored the interesting bits about steady state behavior. Nothing (exce…