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https://www.youtube.com/watch?v=MO0r930Sn_8 https://www.youtube.com/watch?v=MO0r930Sn_8 Richard Feynman explaining magnets is one of the best layman explainers

https://www.youtube.com/watch?v=MO0r930Sn_8 https://www.youtube.com/watch?v=MO0r930Sn_8 Richard Feynman explaining magnets is one of the best layman explainers I've seen (in between the ranting). I honestly didn't understand why magnets worked and found this on a late night youtube binge. (But don't search youtube for anything related to magnets, you end up amongst the perpetual motion nuts) Edit: Just to be clear with this video (it had been a while since I last watched it), he doesn't 'explain' magnets as much as he hints at the concepts involved. I already knew about the spins being lined up etc but it was the "you can't put your hand through the chair" comment that gave me the eureka moment.

ramraj07 6y ago
I rewatch this video constantly. It's not just about magnets, it's about epistemology and it's also the greatest masterclass on science education in my opinion. It's also one of the best distillations of the thirst for finding out that drives humans (at least some of us apparently). Flawed man, it turns out, but am thankful for at least this video if nothing else.
- mensetmanusman 6y ago
  All humans are flawed.
  - etse 6y ago
    Amen
  - Koshkin 6y ago
    Everything in the universe is flawed. (Also, what if it's our "flaws" that define who we are?)
microcolonel 6y ago
For what it's worth, we still don't really know how magnets work; at best we can predict some of their behaviours.
- garmaine 6y ago
  What? No. This is not true. We understand 100% the physics of how magnets work.
  - Koshkin 6y ago
    I guess, depends on who 'we' is. (Besides, do "we" really understand quantum electrodynamics, or we just understand the math?)
    - garmaine 6y ago
      Yes, speaking as a physicist, QED is perfectly understandable.
  - hpcjoe 6y ago
    Not entirely true (that we understand magnetism). We get some things about it. But not everything. The nature of physics is such that we never really have 100% confidence in our theories. We are always looking for things the theory under test doesn't predict correctly in the form of an observation. Which means we have to understand what we are measuring. And how we are measuring it. All of this impacts magnetism. For example, many explanations here discuss electron "spin". Electron "spin" likely doesn't mean the electron is physically spinning. So what is "spin" and how does it actually contribute to magnetism? And then you have a number of interesting QM properties, such as spin-orbit coupling. Remember, the original model of electrons orbiting nuclei was discarded as the electron accelerating around the nucleus would radiate all of its energy away. So classical orbital "motion" of electrons, literally a current, that should generate a magnetic field, which could couple with the spin of the electron, is not really a classical thing. It is quantum mechanical in nature. And we really don't fully grasp QM. Some parts we think we understand and can provide some interpretation to. Other parts ... not so clear. Again, this is why 99 years after Einstein won the Nobel prize, people are still testing relativity, and still testing fundamental/foundational QM. Look at all the work on delayed choice slit experiments[1][2], and many others. Basically we think we have some level of understanding of QM. And we need a strong understanding of QM to understand QM phenomenon. Like magnetism. Its not at 100% understanding yet. May never be. But there is so much more interesting science out there, that this is a good thing. [1] https://www.popularmechanics.com/science/a22280/double-slit-experiment-even-weirder/ https://www.popularmechanics.com/science/a22280/double-slit-... [2] http://www.preposterousuniverse.com/blog/2019/09/21/the-notorious-delayed-choice-quantum-eraser/ http://www.preposterousuniverse.com/blog/2019/09/21/the-noto...
chrisseaton 6y ago
Why does he seem so irritated at the question?
- lxe 6y ago
  A personality quirk. Nothing sinister here.
axaxs 6y ago
I don't know, maybe I'm the odd man out, but I've been linked to this video tens of times and always hated it. I find Feynman comes across extremely condescending and wastes time explaining that the interviewer is too dumb to understand in a very roundabout way. One thing I've come to really respect in my CS career are people not only able but willing to distill knowledge down into an approachable way. I've come across so many people with the same attitude as seen in the video, especially in the DNS world for some reason, maybe that's why it strikes a nerve.
- idolaspecus 6y ago
  I completely agree that his attitude for parts of this video is cringey, but Feynman is famous for (among other things) his ability to simplify and communicate complex ideas. Feynman diagrams are the perfect example of this. Edit: I guess my point is just that being willing and able to communicate simply and effectively is not necessarily at odds with being a condescending prick.
  - garmaine 6y ago
    Except in this case he utterly failed at answering the question and went on an unrelated rant. “What you feel in the magnet is the same force that keeps my hand from going through the chair, so the question is why does it work at a human-scale distance? The answer is that in an iron magnet all the magnetic forces in each atom are aligned. An individual atoms‘ force is too small to be felt at distance, but the combined effect of all the atoms in a magnet is large enough.” That wasn’t so hard.
    - aeternum 6y ago
      The spin of the atoms in my finger are not aligned at all, why would there be any force? Also if it's the same force and it is much stronger when aligned, why don't magnets pass through each other? The much stronger aligned magnetic force should easy overwhelm the weaker force that keeps my hand from going through the chair.
certmd 6y ago
Love the first comment on the youtube video: "RIchard Feyman's wife: "WHY did you not take the trash out yet?!" Richard proceeds to go on a long tirade about electromagnetic forces, gravity, string theory etc. until the wife sighs in despair and takes out the garbage herself. Again."
__MatrixMan__ 6y ago
According to my professor, when I was taking quantum mechanics a few years back, the view that Feynman is prevented from falling through his chair by electromagnetic repulsion is somewhat antiquated. She told us that a more modern perspective puts a greater focus on the Pauli Exclusion Principle. Of course that line of explanation falls to similar loop, re: why do fermions resist sharing state?
- Koshkin 6y ago
  I would like to mention the possibility of tunneling through the chair (however small).
- BeetleB 6y ago
  Indeed, and Freeman Dyson demonstrated this: In 1966, independently of Elliott H. Lieb and Walter Thirring, Dyson and Andrew Lenard published a paper proving that the Pauli exclusion principle plays the main role in the stability of bulk matter. https://en.wikipedia.org/wiki/Freeman_Dyson https://en.wikipedia.org/wiki/Freeman_Dyson

ramraj07 6y ago

I rewatch this video constantly. It's not just about magnets, it's about epistemology and it's also the greatest masterclass on science education in my opinion. It's also one of the best distillations of the thirst for finding out that drives humans (at least some of us apparently). Flawed man, it turns out, but am thankful for at least this video if nothing else.

mensetmanusman 6y ago
All humans are flawed.
- etse 6y ago
  Amen
- Koshkin 6y ago
  Everything in the universe is flawed. (Also, what if it's our "flaws" that define who we are?)

microcolonel 6y ago

For what it's worth, we still don't really know how magnets work; at best we can predict some of their behaviours.

garmaine 6y ago
What? No. This is not true. We understand 100% the physics of how magnets work.
- Koshkin 6y ago
  I guess, depends on who 'we' is. (Besides, do "we" really understand quantum electrodynamics, or we just understand the math?)
  - garmaine 6y ago
    Yes, speaking as a physicist, QED is perfectly understandable.
- hpcjoe 6y ago
  Not entirely true (that we understand magnetism). We get some things about it. But not everything. The nature of physics is such that we never really have 100% confidence in our theories. We are always looking for things the theory under test doesn't predict correctly in the form of an observation. Which means we have to understand what we are measuring. And how we are measuring it. All of this impacts magnetism. For example, many explanations here discuss electron "spin". Electron "spin" likely doesn't mean the electron is physically spinning. So what is "spin" and how does it actually contribute to magnetism? And then you have a number of interesting QM properties, such as spin-orbit coupling. Remember, the original model of electrons orbiting nuclei was discarded as the electron accelerating around the nucleus would radiate all of its energy away. So classical orbital "motion" of electrons, literally a current, that should generate a magnetic field, which could couple with the spin of the electron, is not really a classical thing. It is quantum mechanical in nature. And we really don't fully grasp QM. Some parts we think we understand and can provide some interpretation to. Other parts ... not so clear. Again, this is why 99 years after Einstein won the Nobel prize, people are still testing relativity, and still testing fundamental/foundational QM. Look at all the work on delayed choice slit experiments[1][2], and many others. Basically we think we have some level of understanding of QM. And we need a strong understanding of QM to understand QM phenomenon. Like magnetism. Its not at 100% understanding yet. May never be. But there is so much more interesting science out there, that this is a good thing. [1] https://www.popularmechanics.com/science/a22280/double-slit-experiment-even-weirder/ https://www.popularmechanics.com/science/a22280/double-slit-... [2] http://www.preposterousuniverse.com/blog/2019/09/21/the-notorious-delayed-choice-quantum-eraser/ http://www.preposterousuniverse.com/blog/2019/09/21/the-noto...

chrisseaton 6y ago

Why does he seem so irritated at the question?

lxe 6y ago
A personality quirk. Nothing sinister here.

axaxs 6y ago

I don't know, maybe I'm the odd man out, but I've been linked to this video tens of times and always hated it. I find Feynman comes across extremely condescending and wastes time explaining that the interviewer is too dumb to understand in a very roundabout way. One thing I've come to really respect in my CS career are people not only able but willing to distill knowledge down into an approachable way. I've come across so many people with the same attitude as seen in the video, especially in the DNS world for some reason, maybe that's why it strikes a nerve.

idolaspecus 6y ago
I completely agree that his attitude for parts of this video is cringey, but Feynman is famous for (among other things) his ability to simplify and communicate complex ideas. Feynman diagrams are the perfect example of this. Edit: I guess my point is just that being willing and able to communicate simply and effectively is not necessarily at odds with being a condescending prick.
- garmaine 6y ago
  Except in this case he utterly failed at answering the question and went on an unrelated rant. “What you feel in the magnet is the same force that keeps my hand from going through the chair, so the question is why does it work at a human-scale distance? The answer is that in an iron magnet all the magnetic forces in each atom are aligned. An individual atoms‘ force is too small to be felt at distance, but the combined effect of all the atoms in a magnet is large enough.” That wasn’t so hard.
  - aeternum 6y ago
    The spin of the atoms in my finger are not aligned at all, why would there be any force? Also if it's the same force and it is much stronger when aligned, why don't magnets pass through each other? The much stronger aligned magnetic force should easy overwhelm the weaker force that keeps my hand from going through the chair.

certmd 6y ago

Love the first comment on the youtube video: "RIchard Feyman's wife: "WHY did you not take the trash out yet?!" Richard proceeds to go on a long tirade about electromagnetic forces, gravity, string theory etc. until the wife sighs in despair and takes out the garbage herself. Again."

__MatrixMan__ 6y ago

According to my professor, when I was taking quantum mechanics a few years back, the view that Feynman is prevented from falling through his chair by electromagnetic repulsion is somewhat antiquated. She told us that a more modern perspective puts a greater focus on the Pauli Exclusion Principle. Of course that line of explanation falls to similar loop, re: why do fermions resist sharing state?

Koshkin 6y ago
I would like to mention the possibility of tunneling through the chair (however small).
BeetleB 6y ago
Indeed, and Freeman Dyson demonstrated this: In 1966, independently of Elliott H. Lieb and Walter Thirring, Dyson and Andrew Lenard published a paper proving that the Pauli exclusion principle plays the main role in the stability of bulk matter. https://en.wikipedia.org/wiki/Freeman_Dyson https://en.wikipedia.org/wiki/Freeman_Dyson