Richard Feynman Magnets

nebulajr4 HN recommenders · 2014–2026
999K views · interview · evergreen · Uploaded 2009-04-15

A short clip of Richard Feynman answering an interviewer's question about how magnets work, in which he explains why a why-question has no simple answer without a shared frame of reference.

HN returns to it constantly as a classic on the difficulty of explaining fundamentals and the limits of analogies.

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20 comments from Hacker News

@Luc2014 · in “Questions about Nasa's space drive answered”

I'd really like the source for that quote, because it's dumb for obvious reasons, and I don't know Feynman to be dumb. In fact he said pretty much the opposite to the interviewer asking about magnets in this well known video: [VIDEO]

@AndrewOMartin2014 · in “Why Question Answering Is Hard”

Also there's the problem of context. When someone asks you a question you generally know what kind of answer they expect. In this classic example from Richard Feynman [1] the answer to "Why is Aunt Minnie in the hospital" can be "She broke her hip", "She slipped on the ice and broke her hip", "An ambulance took her there", "Because her husband is concerned for her well being". What's interesting about the Watson approach is that, by taking intelligently composed web pages as input (as opposed to randomly generated texts, or an arbitrary list of atomic facts) the context is already "baked in". Put another way, people make web pages with sentences like "Aunt Minnie is in the hospital because she fell and broke her hip", and don't make web pages with sentences like "Aunt Minnie is in the hospital because the ambulance was headed there and the friction between Aunt Minnie and the bed in the ambulance was high enough to keep them from becoming relatively displaced". [1] [VIDEO] (Edit: I notice, of course, that I have now created a web page with that exact sentence.)

@iaw2014 · in “Study finds possible alternative explanation for dark energy”

I'm a little confused. If I understood the article correctly the argument is that the rate of expansion isn't increasing but staying constant while the rate time passes is slowing. Given that the rate of expansion is a measure of distance over time wouldn't the net effect be identical? I guess the argument is that dark energy is in fact a manifestation of the physical rules of our universe, but in the end doesn't that violate the laws of energy conservation? Effectively if we observe acceleration of distant parts of the galaxy due to present time traveling slower relative to historic, where does the energy that causes the acceleration come from? This is reminiscent of Feynman's explanation about magnetism [1] in that it leads back to the original question. [1] [VIDEO]

@darkmighty2015 · in “Ask HN: What do you wish you had known before you turned 40?”

Tip: Extract useful information from people's mistakes, and show it to them. They'll love it (and it's really fun!). (It's a bit like when you ask a smart physicist a silly question instead of telling you're wrong he'll make the most out of it) Examples: [VIDEO] [LINK]

@Vaskivo2015 · in “”

I'm sceptical about the success of this. Math, for example, isn't something you should theach continuously for two weeks (lets say, teaching multiplication) and then go back to two months later (to teach division). It need continuous practice and reinforcement of it's concepts so that, not only you become proeficient with it, but you also understand how and why it works. Ând the concept of 'topics' reminds me of Richard Feynman's Magnets youtube clip.[0] How indepth is the teacher going to go? I remember "learning" photosynthesis three times. The first time, around 4th or 5th grade was just "CO2 comes in, oxygen comes out. That's why plants are important, yadda yadda". The last time, in my 11th grade I was learning about the physical and molecullar processes that happened inside the plant's cells. There is a clear progression in the complexity. [0] [VIDEO]

@rexignis2015 · in “Richard Feynman on the Challenger disaster (1986) [video]”

I think even Feynman would admit this is not the case, he had no simple way of explaining magnetism because it is inherently complicated. [VIDEO]

@varjag2019 · in “More bad news for controversial 20-year-old claim of dark matter detection”

> Some people have had magnets implanted, leveraging their existing sense of touch into a sense of magnetic fields. Touch is an EM forces interaction, not very different from magnets. [VIDEO]

@keldaris2020 · in “Ask HN: What scientific phenomenon do you wish someone would explain better?”

I'm a physicist specifically working with magnetic systems, but I have very little pre-graduate teaching experience, so take this attempt to answer the question with a grain of salt. The reason some people regard Faraday's original explanation of the eponymous law (it is worth noting that at the time it was widely regarded as inadequate and handwavy) as illuminating is because Faraday visualized his "lines of force" as literal chains of polarized particles in a dielectric medium, thereby providing a seemingly mechanistic local explanation of the observed phenomena. Not much of this mindset survived Maxwell's theoretical program and it has very little to do with how we regard magnetism today. Instead, the unification of electricity and magnetism naturally arises from special relativity, whereas the microscopic basis of magnetism requires quantum mechanics. There isn't really any place for naive contact mechanics in the modern picture of physics, so in that sense I would regard Faraday's view as misleading. Finally, I can't end any "explanation" of magnetism without linking the famous Feynman interview snippet [1] where he's specifically asked about magnetism. It doesn't answer your question directly, but it's worth watching all the more because of it. [1] [VIDEO]

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@rimunroe2020 · in “Neutrino Particles May Be a Link to the Dark Sector”

I appreciate it. You're absolutely right about how exciting it is to be able to share explanations with people. This is a video of Feynman's answer to an interviewer asking about what and why you feel something when you put two magnets together [VIDEO] . It's a great description of the problems inherent to explaining this sort of thing to people. (Also, if anyone knows a video/essay/talk along these lines by a less sexist person, I'd love a link.)

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@aunty_helen2020 · in “Bohr–van Leeuwen theorem – magnetism in solids is a quantum mechanical effect”

[VIDEO] 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.

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@acqq2020 · in “Bohr–van Leeuwen theorem – magnetism in solids is a quantum mechanical effect”

I like the comments: 1) "- How do magnets work? - Oh, they're just a bunch of nano-magnets" 2) "Yes, but why? Still it's a description, not an explanation" 3) "To 2: [VIDEO] check it out. I really is that way"

@lupire2022 · in “Ask HN: What is a nature of a magnetic field”

One of the world's best expert and teacher said: "It's just one of those things that you have to take as an element of the world.... I can't explain the attraction in terms of anything else that's familiar to you." [VIDEO]

@deckard12022 · in “Elasticsearch SQL”

> at least tweak some things That's really understating the problem. Oracle, for example, can be wildly different from MySQL or PostgreSQL. SQLite makes selects extremely cheap, so cheap, that if you try to do a straight migration to a server-based DB it will probably just choke. Assuming any devs on your team realized the benefits of SQLite and took advantage of them. But it gets worst with SQL on things that are not relational DBs. The exact person that SQL-on-Elasticsearch is designed for is also going to be the person that won't know the idiosyncrasies of Elasticsearch well enough to know when they are in trouble.[1] They will end up trying to get explanations for what is going on in Elasticsearch in terms of what they know (i.e. SQL on a relational DB). The end result will then be confusion and ultimately re-learning Elasticsearch from the ground up. [1] [VIDEO]

@bsza2023 · in “Tesla shares 48V architecture with other automakers to move the industry”

> they admit they don't now why that happens No, they said “not sufficiently qualified to explain”. Which is not the same as not knowing, given that the same phenomenon can be explained on a lot of different levels depending on when you get tired of asking “why?” - see this video of Richard Feynman “explaining” magnets: [VIDEO]

@16bytes2024 · in “James Webb Telescope Confirms That the Universe Is Expanding at Different Speeds”

To paraphrase Feynman, I can't explain to you how the universe expands in terms that you are familiar with because I don't understand it in terms that you are familiar with. [VIDEO] It takes effort to understand those fundamental terms, so if you want to understand this, you'll have to meet people halfway instead of rejecting how somebody is trying to explain something to you.

@antognini2024 · in “Why the Higgs Field Is Nothing Like Molasses, Soup, or a Crowd”

There's a clip from a short documentary about Richard Feynman in which the interviewer asks him to explain what's going on when you try to push two magnets together head-to-head. Feynman basically says that he could tell you a story like "there are rubber bands pulling the magnets together," but it would be a lie and that if you really want an explanation you have to learn the physics. [VIDEO]

@ramraj072025 · in “I should have loved biology too”

I don't know if just going to nature is sufficient to get fascinated with biology. In my opinion it takes a fundamental reset in how you think about anything you see. Humans while smart have obviously had to learn to "ignore" thinking about how things work. You don't think too hard about how anything works really. I mean at a cursory level sure, but by vastly different interpretations of the word "cursory", you can change your thirst to know how things you see work at more and more fundamental levels. You don't need to go into nature to get this curiosity except for the possibility that it makes you more meditative. You can look at your arm and think what the hell happens in there at a molecular level to make you move the muscles. Or when someone says nerves conduct electricity what the hell does that mean? I revisit this feynman video of him explaining (or not) magnets every few months and I think it's relevant to this question. [VIDEO] When I think like that I'm just curious why OP and others blame teachers or whoever else for not inducting the curiosity in them. Like it's someone else's job to make you curious? In my opinion you're either born that way or you're not. Some airport store book isn't gonna make you the next whatever scientist you adulate.

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@baq2025 · in “New magnetic component discovered in the Faraday effect”

Just listen to Feynmann trying to explain why he can't explain magnetism in macro terms (e.g. [VIDEO] )

@1-more2026 · in “Juggalo Makeup Blocks Facial Recognition Technology”

Here's the thing about "fucking magnets; how do they work?" How do magnets work? No less a science communicator than Richard Feynman—he of the rubber sheet gravity spacetime analogy—had no analogy to communicate why ferromagnetism creates attraction and repulsion. Here's his incredibly shaggy dog non-answer to the question about how magnets work wherein he says that there are no pat answers to "why" questions. He gets to the money line: "I cannot explain that attraction in terms of anything else that's familiar to you" [VIDEO] So I will defend that line in the song. I will only accept answers from people who can explain why ferromagnetism works to me assuming I know how electromagnets create magnetic fields.

@zkmon2026 · in “Why Is Europe Burning?”

Two issues with the title. Global warming is not specific to Europe (it is "global"). And the "why" can't be meaningfully answered unless you specify how far you want to go along the cause-and-effect chain (Feynman on magnetism - [VIDEO] ). Let me look at cause-and-effect chain for the past 100 years. It is the unbridled industrialisation, captial markets, business push, desire to dominate other countries, vote-bank democracies, exploitation of natural resources and so on. It is not something caused by single person or policy over past few years or decades.