Sunday, June 02, 2013

Richard Feynman: Fun To Imagine

You must have seen many excerpts from the following video featuring Richard Feynman:

But maybe you have never watched the whole 66-minute-long video. Here it's waiting for you.

He covers lots of things – need for imagination in physics; heat is wiggling; surface tension is the attempts of molecules to get in...

In a similar way, he explains using the atomic language why gases cool down when they expand. And thousands of other fun things...

Various atoms like each other to various degrees. Wood and oxygen. They get caught and create lots of jiggling which is spread elsewhere and what you get a catastrophe. The catastrophe is called fire. ;-)

Where the did carbon get there from? It came from the air. The wood is from the air: it grew by absorbing carbon dioxide. Just a little bit from the ground. These anthromorphic stories about the life of the atoms sound funny.

He also traces the energy – it ultimate comes from the Sun. Where did the Sun find the jiggling (energy)? He has to stop somewhere...

How do rubber bands work? There are chains of molecules but other molecules are jiggling and hitting the chains, trying to shorten them. It only works when the rubber is warm – heat is necessary. Rubber bands' temperature goes up when you stretch them and vice versa. The jiggling is inside everything.

Around 14:40, the scene about "what the magnets feel" starts. You must have already seen this exchange. An irritated Feynman repeats the claim of the author of the question that it's an excellent question but makes it very clear that the question was utterly idiotic, too. When we ask "why", we must have some facts that we're allowed to use as more fundamental facts, parts of the answer. Magnetism is more fundamental than the macroscopic events we know from the everyday life.

At 22:07, we switch to a dentist and a water dam. Turning wheels in the dam make all the wheels in the city turn. It's all about iron and copper, a natural thing. Again, he points out that there are long-range forces that are more fundamental than the "direct touch" forces we know. Gravity is much weaker; but it may matter when the electric forces etc. get neutralized.

31:40, fraternity at MIT gives questions like: Why you get left-right but not upside-down reflected in the mirror? ;-) A fellow Junior Fellow in the Society of Fellows (humanities) was impressed by this question and didn't want to believe that I could solve such a problem. ;-) The actual mirror only reflects the front-rear direction. We just psychologically imagine that the image is rotated around the horizontal axis – this rotation is a symmetry unbroken by the gravitational field – which makes the image left-right reflected.

34:50, what keeps the train on the tracks? The planes of contact are tilted, regulating the direction back if the train is destabilized much like the differential – something that the trains don't need.

37:20, seeing things. A not too pretty woman sitting in the swimming pool allows one to watch the waves instead. Sensitive spots in the eye. Mess of waves in the space (electromagnetic fields with all the frequency modes) and complicated mechanisms in the eyes and radios. As a kid, I was also stunned when I realized the idea that all the information about all the radio and TV stations is flying around me in the room at the same moment.

At 43:20, he talks about scales. Big numbers. You scale yourself to imagine them. Why Earth is round. Nuclear fuel. Neutron star matter – balancing gravity and pressure. Pulsars – they're the same thing. Immense densities, confirmation of predictions. Black holes.

54:30, ordinary people like Feynman can master these things. There are no miracle people. With some investment of time, he becomes a scientist. A bit too idealistic. 55:20, his research is a nutty mixture of equations, ideas, and vague pictures of equations. In every man's head, the imagery is probably very different from others. Translation engines work hard. He thinks so because different people solve problems differently. Feynman couldn't do counting multitasking; someone else uses an optical system for counting.

1:00:55, I have already linked to this many times. We're used to understand very different phenomena than the fundamental ones. Quantum mechanics is wonderfully different than the macroscopic world. People who try to reduce QM to some mundane or classical mechanism will be defeated.

Incidentally, when I talk about quantum mechanics, let me modestly mention that the first tag in the history has earned a gold badge on the Physics Stack Exchange. Which tag was that? Yup, it was quantum mechanics. Congratulations to Bohr, Heisenberg, Dirac, Schrödinger, Pauli, and a few others, too! ;-)


  1. The idea that a mirror reverses left and right always seemed stupid to me, because if it does, there is no plausible physical reason why it should not also reverse top and bottom.

  2. The left-right swap due to mirror is seen ONLY because eyes are distributed on a horizontal line stupid! If they were distributed vertically you would see up-down swap. Turn your head by pi/2 in front of the mirror if you like.

  3. Back to that swimming pool analogy: Is there any way an "eye" (vertical slit) at some particular location on the edge of the water line could decipher information coming from a particular object in the water despite all the sloshing from other objects in the pool?

  4. If you look with only one eye the mirror still swaps left-right, so the distribution of the 2 eyes is irrelevant.

  5. Then close one eye. Does that change something? Or imagine someone who never had more than one working eye.

  6. Delightful guy, this Feynman!

  7. He is indeed. However at around 15:00 the guy asks Feynman what is going on between two magnets, how are they doing it etc... Feynman doesn't understand the question and goes on and on about the difficulty of the "why" question... Eventually he gives the beginning of an answer ie electro-magnetic forces. But we have to go through the whole condescending philosophical approach of the way a question is turned and blah blah... I guess it's the foreplay before the thrill... They had a lot of time in those days ;-)

  8. Dear Shannon, apologies for the reduced harmony between us ;-) but I happen to disagree with you. The general introduction Feynman gave to explain that the question is meaningless without the right context is arguably more important than anything specific that he said about magnetism.

    There exists a tendency among the laymen to think that whenever they ask "why", "why does this exist" and so on, it's a deep question and they're really big thinkers, even if they blindly continue to ask why de facto indefinitely.

    But this ain't the case. Most of such "why" questions are just meaningless. A necessary condition for a "why" question is that the person who asks the question must know some truths that he or she finds acceptable or unquestionable that may be used as the ultimate axioms that meaningful answers may ultimately boil the questions to.

    Many laymen ask the why questions in the meaningless, impotent way - they ask questions just for the sake of asking anything - and they don't actually seem to be interested in the answers (any answers) because

    1) in most cases, they don't seem to actively know anything that the answers may use as the axioms or truths

    2) if they think that they know something "fundamental", these things are usually not fundamental at all

    3) they seem to never adjust their wrong ideas about what is fundamental and what is not. More generally, they never seem to learn anything new.

    I personally get as irritated by similar "why" questions as Feynman did because they mostly show that the people who ask them know nothing about Nature - they have learned nothing from either of their previous iterations of the "why" questions - but they also seem to indicate that they think that they're immensely smart or deep. They're not smart or deep at all, they are uneducated, independently unthinking idiots who just want to pretend to be smart, and that's something I just can't stand.

    This theme is visible almost everywhere in the "popular science" industry surrounding science. Readers of junk popular books - I don't mean just the ultimate superstinky shit, using very diplomatic words, similar to Smolin's demagogy but a much broader selection of garbage - are being led to ask "why" all the time and feel "smart" while asking "why" but they're also taught to never listen to any answers and never learn anything important about Nature or correct their misconceptions.

  9. I soo much identified with his response to the question!

  10. Yes, Luke, it is possible to focus on a particular frequency or interval of frequencies; and it is also possible to focus on waves coming from a particular direction or interval (or solid angle) of directions.

    The former is achieved by all the things using resonance. For example, a radio is sensitive to all waves but the response may be made to strengthen dramatically for waves with frequencies around an "f" that may be adjusted. It's a mathematically isomorphic mechanism as any other resonance in Nature - for example, you may make a small bridge swing back and forth if you periodically push it with the right frequency.

    The latter may also be achieved. Well, one may surely pick light rays coming from a particular direction, e.g. by two holes behind each other.

  11. Just want to say I agree with JP and Andre - this interpretation of optical perceptions has nothing to do with the number of eyes or their arrangement.

  12. Right, exactly. That's a paradox. But some people take the "fact" that the mirror reverts left and right as a given "self-evident fact" that can't be challenged. For them, the "self-evident fact" implies a paradox, exactly for the reason you mentioned, and they ask how it's possible that Nature has such paradoxes. Of course that the right answer ultimately is that their assumptions include a "stupid idea", as you called it. The resolution of paradoxes is *always* a stupid idea included among the assumptions.

  13. Dear Lubos, It's ok to disagree ;-). When does the guy ask "why" ? Never. Also he doesn't ask the question for himself but for laymen/learners/swines who will watch the interview. I actually feel he knew to avoid the why with a physicist, he says "what is the feeling of..." or "how are the magnets doing it?", "how does it work?"... never does he asks why. Feynman twisted it. I like Feynman's talks very very much. It seems to be too much of a challenge to ask simple questions to geniuses... (bit like Sheldon Cooper).

    PS. I hope you are surviving the terrible floods in your town Lubos. The news we get here are terrible.

  14. Feynman's remark that he was just an ordinary person with an ordinary head who thought long and hard about physics was diplomatically disingenuous. He knew people are not all the same and remarked elsewhere that education doesn't reduce but magnifies the differences.

    Here's an inside look at what uneducable people are really like:

    I must admit that in my old age I'm pretty uneducable myself like the boy in the story. It's one thing to get a glimpse of the truth and quite another to store it in long-term memory.

  15. Dear Shannon, I called it the "why" question because structurally, it is a "why" question.

    But if you insist to literally quote what the guy actually asked, he asked "what is it, the feeling between those two magnets", which is surely much more idiotic than just asking "why" from a physicist's viewpoint.

    Physics isn't about "feelings" and there are no "feelings" in between the magnets, anyway. If one "feels" that the magnets repel, he feels it simply because he has to stretch his own muscles to compensate an actual - magnetic - force - so of course that he feels that his muscles are being stretched.

    Feynman answered those things specific to the interviewer's formulation of the question - about "what is the feeling" - immediately but it was equally clear that these feelings were not really what he was asking.

    Water is in some places where it shouldn't be but of course that for 99.99% of people like me, it's nothing else than an annoying rain and cloudy weather. The politicians overreact much like the journalists, so despite the recommendations by experts etc., schools and parts of the Prague subway, among other things, were closed and an elevated emergency condition were declared in 12 regions of Czechia out of 14.

    It will stop raining tonight or so. We expect a sunny weather on Wednesday.

    The floods have no chance to compete with the August 2002 floods, for example.

  16. Well, yes and no, Luke. I feel that there's lots of honesty in that remark by Feynman. He primarily meant his background and education as a young kid. His parents were very far from any academic positions - or any college-based occupations, for that matter.

    That's relatively rare in the Academia, especially top Academia, and I can tell you something about it because my parental background has been as free of colleges as his. This implies a very different composition of habits etc. that are being hardwired into the pupil and very different strategies and motivations that lead the kid to learn physics or maths at a young age, something that I know too well, too. There's nothing in the environment that would "encourage" one to do "clever" things at all.

    Now, he was clearly smart but there had to be a sense - because genetics works, stupid - in which he was structurally similar to his parents who were much closer to average people than to very smart ones. So I feel that he was mostly proud to be a self-made man and as far as I can say, rightfully so.

  17. Speaking of which, Susskind was a plumber's son. But both he and Feynman were (I think) 2nd generation Ashkenazi Americans, which helps explain that. Your case sounds more extraordinary. Though I can think of others: Gauss's parents were peasants weren't they? Benjamin Franklin was the last of 17 children born to a candle-maker who had only one year of formal education and ran away from home. Lincoln was the son of a ne'er-do-well backwoodsman with one year of formal education. He grew up barefoot and led a life of hard physical labor between the ages of eight and twenty-one.

  18. Hi Luke, I enjoyed reading that blog. In my opinion, the mystery is not that so many students (myself included) start forgetting the algebra they learned within weeks, it's that there are students who don't quickly forget.

    It's partly domain-independent -- European and U.S. kids would start forgetting Chinese very quickly if they did not constantly use it, too -- and partly, I am sure, domain-related: we've had a hundred thousand years or so of parallel, mutually influencing evolution of language and human genetics. Stands to reason that the language-processing centers in the brain must be large.

    However, arithmetic beyond simple counting has been part of civilization only for a few millennia. That means of us without math-friendly genes have not yet been selected out of the gene pool.

    Until parents gain the ability to choose their designer-DNA kids out of a catalog, the compassionate thing to do would be to tailor math instruction to the actual abilities of pupils, slash the curriculum for all but a fast-tracked minority, and rely on drills and frequent practical exercises to revisit previously covered ground, again and again. Chop the feel-good courses to make room for this change.

    Feynman, according to Gleick's biography, benefited from free "math labs" offered in the evenings by volunteer teachers in NYC that really challenged and expanded young minds. So in that sense, he may have had an advantage over ten-year olds whose hometown did not afford such opportunities to talented children.

  19. I thought Feynman wanted to say the forces between two magnets questions is a bad and not well enough defined one ... ;-)

    This made me chuckle by myself thinking that we could need the help of Feynman at Physics SE too to do away efficiently with the flood of really crapy questions of non-physicists (Programmers etc) , who have really no clue about the most basic things every high school kid knows. These knowreallynothings ask for example "what is velocity"

    or they have never heard about the difference between solids and liquids

    and the crap does not get closed but gets even highly upvoted often (But reference questions important for researchers get closed by David Zaslavsky, damn him!). Ok, the second question has some astonishingly acceptable answers, but it illustrates too the fact that John Rennie can say what he wants (make mistakes etc) and gets upvoted by the crowed, even if he bullies AdS/CFT for example by saying it has now useful applications etc...

  20. I agree. For many children, maybe most, it would be good enough if they could learn how to add and subtract, multiply and divide -- and use a calculator. If we set our sights lower we might get better results.

  21. I didn't want to make the message too long, so I omitted discussion of why it's a stupid idea. When you raise your right hand, the hand raised by the person in the mirror is on your right. This must present some kind of problem for the stupid idea. Well, the stupid idea misses the fact that left and right are subjective (defined from the standpoint of the subject). If the person in the mirror were to raise his right hand, that would be a reversal - thanks to his intelligence, and in that case there'd be something to worry about. :-) Still, though, I'm a little worried, wondering if there could be a world in which top and bottom were subjective.

  22. Dilaton, I didn't know they were answering this type of questions on Physics SE (I rarely go on this site). It seems to be the Physics agora ;-).

  23. Hi Luke, you either misunderstood me or, more likely, I expressed myself poorly. Yes, + - * /, plus a number of minor but tremendously useful "tricks" such as the Rule of Three, are the absolute floor that every human, save the severely handicapped, must have. This knowledge can be imparted by the end of elementary school, certainly no later than sixth grade. But what, and how, to teach them for the intervening years before their graduation?

    In my opinion, you want to teach them as much as possible, but at the same time take into account the "hard disk gets overwritten" phenomenon. My guess is that for most of us, while our brain's internal memory bank for math is "too small", constant repetition should help to enlarge it. Rather than teaching twenty, or thirty, different mathematical topics, of which at best two or three will be remembered, select only five or ten but drill and repeat and review and practice, so thoroughly and so often, that they become ingrained.

    I remember private tutoring that my parents shelled out money for in high school. The tutor, a university student of mathematics, at first was excited that I learned so quickly. When I had forgotten everything two weeks later, he was deeply hurt and saddened. He did not know about the problem of the "too small hard disk".

    If the blog you linked to is a reliable indication, this situation has not gotten better. Maybe there is more special education at the ends of the spectrum today -- for the gifted and the handicapped -- but the broad middle is still not being taught so as to make the most of their potential while taking into account their limitations.

  24. After arithmetic they start practicing it on subjects like carpentry, cooking, making sure your employer paid you every cent he owes (don't laugh, I had an employee who searched me in the eye to answer that question because he couldn't multiply) and other things that we encounter in daily life. I'm big on all things practical: