7 ms·

They take all paths weighted by resistance.

by imtringued 4y ago

xracy 4y ago
I feel like you just saved me 22m
- version_five 4y ago
  It's funny how we used to say "a picture is worth a thousand words", and now a YouTube video is worth about five words.
  - GaggiX 4y ago
    To be honest the video OP linked is really good at teaching about electricity if you don't know much about it (and create a useful mental model).
    - marcosdumay 4y ago
      From the amount of people confused here, I'm doubting this. It is very interesting. But that doesn't make it good at teaching.
      - mrguyorama 4y ago
        Half of HN would be confused about a ham sandwich while confidently declaring the teacher wrong.
  - kccqzy 4y ago
    The right picture is worth a thousand words. The wrong 39600 pictures (22 minutes x 60 x 30 fps) are worth a lot fewer words.
    - mattigames 4y ago
      What have you done? Now we need to rewrite them all! "The right bird in the hand of worth more than 2 right ones in the bush"
      - marcosdumay 4y ago
        Oh, man, if you don't think the difference is important it's because you never had the wrong bird on your hands.
  - FridayoLeary 4y ago
    You can also say that one forum discussion is worth a dozen blog articles. SEO ruins the internet.
- NotYourLawyer 4y ago
  Nah it’s a good video. Solid change in general.
  - NotYourLawyer 4y ago
    *channel
- deleted 4y ago
  [deleted]
KRAKRISMOTT 4y ago
With the path integral being an analogue computer.
beerandt 4y ago
The same way (well, similar way) water flows through pipes or otherwise. How does water "solve" a maze to an open tap?
- sfifs 4y ago
  That's analogy is not really correct. Nor is the one in the video. With electrons, or light for that matter you're dealing with wave particle duality and the appearance of "shortest path" is a result of the particle's wave nature. Prof Morales did a good explanatory series in Ars https://www.google.com/amp/s/arstechnica.com/science/2021/01/the-curious-observers-guide-to-quantum-mechanics/amp/ https://www.google.com/amp/s/arstechnica.com/science/2021/01... Water doesn't actually "solve" a maze either https://youtu.be/81ebWToAnvA https://youtu.be/81ebWToAnvA
  - beerandt 4y ago
    Depends on how you set up the analogy, but sure it's not perfect. And I put "solve" in quotes precisely because it does no such thing. But a water molecule interacting with pressure gradients and waves is about the best eli5 or even eli18 that I've seen, with both particle and wave representations. But maybe that's just because I'm a hydraulics engineer and "get it."
    - version_five 4y ago
      Your analogy is fine for a classical treatment of electricity. At some quantum level I assume it's also wrong for water, but that's irrelevant.
      - beerandt 4y ago
        Yea, but we're talking about a 22 min video vs a 2 sentence explainer to grasp the very basics of a concept here. I love to argue the technical stuff as much as anyone, but the underappreciated aspect and skill of any engineering is eyeballing cost/benefit of any expenditure. Be it sizing elements of finite analysis, or sizing an analogy.
function_seven 4y ago
This begs the question the video is trying to answer. Imagine you have no experience or knowledge of what electricity is or how it works. Then you learn the bare basics. You might have this same question, "how does it 'know' which path has the least resistance?" The pepper demonstration in the video is a good analogy to show how the resistance information of every possible path (or, really, stub) is "back-propagated" to the branching point. No, it's not a perfect description of what is really going on, but I dare say there's no such thing. Just better and better models. If I have a wire that connects from (+) to (-) on a battery, and a dozen wires that branch off of (-) and go nowhere, how does the current "know" not to waste time trying each of those stubs? This video explains that.
- 11101010001100 4y ago
  it doesn't know. it 'samples' or whatever inadequate word you wish to use.
  - ShamelessC 4y ago
    [flagged]
- Dylan16807 4y ago
  > This begs the question the video is trying to answer. Imagine you have no experience or knowledge of what electricity is or how it works. Then you learn the bare basics. You might have this same question, "how does it 'know' which path has the least resistance?" You're still saying "path of least resistance" though. A very important part of the answer is that it doesn't find it. All paths carry electricity. So "take all paths" isn't begging the question, it's correcting the question, and "weighted by resistance" isn't begging the question, it's giving a pretty easy answer to anyone that understands the concept of "resistance" in a non-electrical sense that some paths let things through more easily than others. And if you have a bunch of stubs, the electricity does go onto them. It just gets stuck at the end.
  - mfringel 4y ago
hgsgm 4y ago
It's even simpler if you look at parallel resistors by their conductance (more paths), and series resistors by their resistance (steeper path). As usual, more symmetrical math makes the engineering less mysterious.

They take all paths weighted by resistance.

xracy 4y ago

I feel like you just saved me 22m

version_five 4y ago
It's funny how we used to say "a picture is worth a thousand words", and now a YouTube video is worth about five words.
- GaggiX 4y ago
  To be honest the video OP linked is really good at teaching about electricity if you don't know much about it (and create a useful mental model).
  - marcosdumay 4y ago
    From the amount of people confused here, I'm doubting this. It is very interesting. But that doesn't make it good at teaching.
    - mrguyorama 4y ago
      Half of HN would be confused about a ham sandwich while confidently declaring the teacher wrong.
- kccqzy 4y ago
  The right picture is worth a thousand words. The wrong 39600 pictures (22 minutes x 60 x 30 fps) are worth a lot fewer words.
  - mattigames 4y ago
    What have you done? Now we need to rewrite them all! "The right bird in the hand of worth more than 2 right ones in the bush"
    - marcosdumay 4y ago
      Oh, man, if you don't think the difference is important it's because you never had the wrong bird on your hands.
- FridayoLeary 4y ago
  You can also say that one forum discussion is worth a dozen blog articles. SEO ruins the internet.
NotYourLawyer 4y ago
Nah it’s a good video. Solid change in general.
- NotYourLawyer 4y ago
  *channel
deleted 4y ago
[deleted]

KRAKRISMOTT 4y ago

With the path integral being an analogue computer.

beerandt 4y ago

The same way (well, similar way) water flows through pipes or otherwise. How does water "solve" a maze to an open tap?

sfifs 4y ago
That's analogy is not really correct. Nor is the one in the video. With electrons, or light for that matter you're dealing with wave particle duality and the appearance of "shortest path" is a result of the particle's wave nature. Prof Morales did a good explanatory series in Ars https://www.google.com/amp/s/arstechnica.com/science/2021/01/the-curious-observers-guide-to-quantum-mechanics/amp/ https://www.google.com/amp/s/arstechnica.com/science/2021/01... Water doesn't actually "solve" a maze either https://youtu.be/81ebWToAnvA https://youtu.be/81ebWToAnvA
- beerandt 4y ago
  Depends on how you set up the analogy, but sure it's not perfect. And I put "solve" in quotes precisely because it does no such thing. But a water molecule interacting with pressure gradients and waves is about the best eli5 or even eli18 that I've seen, with both particle and wave representations. But maybe that's just because I'm a hydraulics engineer and "get it."
  - version_five 4y ago
    Your analogy is fine for a classical treatment of electricity. At some quantum level I assume it's also wrong for water, but that's irrelevant.
    - beerandt 4y ago
      Yea, but we're talking about a 22 min video vs a 2 sentence explainer to grasp the very basics of a concept here. I love to argue the technical stuff as much as anyone, but the underappreciated aspect and skill of any engineering is eyeballing cost/benefit of any expenditure. Be it sizing elements of finite analysis, or sizing an analogy.

function_seven 4y ago

This begs the question the video is trying to answer. Imagine you have no experience or knowledge of what electricity is or how it works. Then you learn the bare basics. You might have this same question, "how does it 'know' which path has the least resistance?" The pepper demonstration in the video is a good analogy to show how the resistance information of every possible path (or, really, stub) is "back-propagated" to the branching point. No, it's not a perfect description of what is really going on, but I dare say there's no such thing. Just better and better models. If I have a wire that connects from (+) to (-) on a battery, and a dozen wires that branch off of (-) and go nowhere, how does the current "know" not to waste time trying each of those stubs? This video explains that.

11101010001100 4y ago
it doesn't know. it 'samples' or whatever inadequate word you wish to use.
- ShamelessC 4y ago
  [flagged]
Dylan16807 4y ago
> This begs the question the video is trying to answer. Imagine you have no experience or knowledge of what electricity is or how it works. Then you learn the bare basics. You might have this same question, "how does it 'know' which path has the least resistance?" You're still saying "path of least resistance" though. A very important part of the answer is that it doesn't find it. All paths carry electricity. So "take all paths" isn't begging the question, it's correcting the question, and "weighted by resistance" isn't begging the question, it's giving a pretty easy answer to anyone that understands the concept of "resistance" in a non-electrical sense that some paths let things through more easily than others. And if you have a bunch of stubs, the electricity does go onto them. It just gets stuck at the end.
- mfringel 4y ago

hgsgm 4y ago

It's even simpler if you look at parallel resistors by their conductance (more paths), and series resistors by their resistance (steeper path). As usual, more symmetrical math makes the engineering less mysterious.