Interview with Walter Levin. About physics, art, secrets of teaching and the main mysteries of the universe
In April 2017, we interviewed Walter Levin , a legendary lecturer, astrophysicist, author of The Eyes of Physics: A Journey from the Edge of the Rainbow to the Frontier of Time, a former MIT professor . His farewell lecture, “For the Love of Physics,” scored nearly 6 million views on YouTube.
We talked about science, teaching, personal interests and the most mysterious objects in the Universe: the video version of the interview here , adapted for reading - under the cut.
Vert Dider: Today, our guest is a former MIT professor, one of the most famous physicists and teachers in the world - Walter Levin. You probably remember his lecture “In the name of physics” in the translation of Vert Dider or his book, for example, “Through the Eyes of Physics” , which the publishing house “Myth” published in Russian. Somehow read.
So, Walter, I think we will start with a few personal questions.
The first and perhaps most important: what inspired you to go to physics?
Walter Lewin:In fact, the answer to this question is rather trivial. This is how it all started: I was pretty good at school, I had a penchant for science, but not for languages. Then I had to decide where to go: I was given a mathematics, but it didn’t fit in my head that I could connect my life with it - so that was past. I also loved chemistry, but as it seemed to me then, the main thing was to cram there, and not to understand the concepts, but I have a terrible memory - so by. I still have this choice: biology, living physics, or physics. In Holland, to study biology, it is necessary that Latin and Greek be in school - I did not have them. So I chose physics by elimination, not so much from big love. Who knew that I would fall in love with physics and she would repay me in return: my life is so intertwined with physics that I now say that physics is my life, and art is my love. By this I breathe.
VD: I am glad that you mentioned art - this is our second question: what kind of art do you like most and who is your favorite artist?
W. Lewin: I have fifty favorite artists, no less. Although I do not have a formal education in art, I carefully studied art history, my wife holds a Master of Art History degree, and I even read lectures about her. Immodest statement, but in art I understand well. The only thing that interests me in it is the pioneers. What I like or not is much less important than a kind of invention, breakthroughs. In physics, the same thing. My personal preferences play no role, it is important who made this breakthrough. I will name the creators and innovators of the first quarter of the twentieth century. One of them is Malevich .
Suprematism changed the world: 1915, his “White on White” and “Black Square” - they changed the world. Just like Mondrian and Picasso , like Matisse , and Kandinsky , and Brancusi . But I single out Malevich among them. And I cannot have any favorite figures of art ... I don’t even have any favorite direction in art - they are all so amazing. Suprematism is a great reaction to post-impressionism, as is Mondrian’s neoplasticism .
Or remember the Dadaists . Duchampturned the very concept of art. He wrote a portrait of Mona Lisa and added a mustache to her, and wrote “LHOOQ” below. If you quickly read it in French, you get "She has a hot ass." What is the provocation. In 1917, Duchamp took an ordinary urinal, turned it ninety degrees, and sent it to an exhibition of a society of independent artists. They could not refuse to exhibit it: Duchamp was in society. The exhibit was sent to the basement - scared. The same urinal, like that, is now worth ten million. He changed the very concept of art. Do I like that urinal? - Well no. Do I like a work of art, one of the most important phenomena in art, comparable to the “Avignon maidens” by Picasso in 1907? Is that picture beautiful with girls? - Nah, ugliness. I often see her at exhibitions, for example, in New York. This is probably The most famous painting of the twentieth century. Disgusting, but the most important.
This is because I do not have a favorite artist, I love innovation, breakthroughs.
VD: Still, it’s interesting to ask: you said that you feel the same way about physics. For example, over the past hundred years, what discoveries in this area would you call the most important? If we talk about the pioneers.
Walter Lewin: The most important for the twentieth century?
VD: Yes, the twentieth or maybe even the twenty-first.
Walter Lewin: In the twentieth century, quantum mechanics became the most important discovery, a global breakthrough that happened in the twenties. Not only physics has changed radically, but the approach to it itself. We all think in terms of Newtonian physics. Every person on Earth, even theoretical physicists, think in a similar way. And why? - They were born, they had a bottle from which they drank milk, they played with baseball and tennis balls, they threw them and caught ... and each such event is determined - you can throw a ball, “help” him with a racket, and he will be the same to ride.
In quantum mechanics there is no such certainty. That is, we cannot imagine or understand it. This is the most counterintuitive area of physics, but this is how the world works at the level of molecules and atoms, it is not deterministic. And this was an incredible breakthrough.
And of course, in 1905, Einstein and the special theory of relativity. She turned our understanding of space and time. Even more surprising thing - it was the year 1915, the general theory of relativity. She opened for us a new understanding of gravity. Well, yes, Newton's theories were correct and unusually accurate, but Einstein turned out to be more accurate by presenting small corrections to our fundamental understanding of the world, namely: the gravitational distortion of spacetime.
VD: Since you mentioned gravity ... One of the questions that is now being discussed among scientists is whether it is possible to create a particle-based theory of gravity. Quantum theory of gravity - how likely is it, in your opinion?
Walter Lewin: This is, of course, a kind of "holy grail" of physics. If we consider smaller and smaller scales, we will rest on a singularity, the same as in the heart of every black hole. Singularity has no size. It has no size, but there is a mass - and what it is! - It can be a billion times heavier than the Sun. Or, for example, twenty times. Accordingly, the density is infinitely large, the size - on the contrary. What do physicists do? There is no quantum gravity yet. Black holes probably have some levels of quantization, but we probably don’t know. And our only hope is string theory. They came as close as possible to the creation of quantum theory, but so far it is early to speak about their successes, of course. Such a theory does not yet exist. It will be one of the greatest breakthroughs of science.
VD: Do you think there is a chance to open a graviton ?
Walter Lewin: This is an interesting question. If we take the graviton as a theoretical, hypothetical particle that transfers the charge of gravity in much the same way as photons in electromagnetic radiation transfer the power of electromagnetism ... Yes, for me, this is quite likely. We can easily measure photons ... Measuring gravitons may not be such a simple task. Maybe they are wrapped up in some other dimension, and it may turn out to be so small that we will never find it. So this is a probability with a big question mark. I do not want to make predictions about whether gravitons will ever open. But in general, physicists have almost no doubt that they endure gravity. By the way, gravitons have no mass ..
VD: No mass?
Walter Lewin: Very strange particles.
VD: You've already mentioned string theory. Several people sent us a request to ask you about it, this theory raises many questions. Theory is not like all physicists.
What do you think of string theory? Is it helpful? Will she make any discoveries or learn something?
Walter Lewin: String theory is very important: only it gives hope, sooner or later, to develop a theory of quantum gravity. The development of string theory led to some results. Not to say that significant, but they showed its potential. Whether scientists have achieved the ultimate goal of string theory, whether they will create a theory of quantum gravity is another question.
String theory is based on the idea of particles as oscillating strings of incredibly small size, about ten to minus thirty-three degrees of a meter. It is even impossible to imagine how small they are. If we increase the atom to the size of our galaxy, to hundreds of thousands of light years, the strings will still be less than a millimeter in size ... I hope I was not mistaken with my calculations ... So, ten to the minus thirty fifth degree is a very small part of a millimeter. But, of course, this is not the reason to think that the theory is wrong.
I am optimistic about string theory, but to a large extent it’s like a crane in the sky.
So, the mistake I still crept. The size of the strings will be a tenth of a millimeter.
VD: Oh, one tenth, that is, even less.
Walter Lewin: An atom is ten to the minus tenth of a meter, that is, one tenth of a billionth of a meter. And if this crumb is increased to the size of a galaxy, then one string will be no more than a tenth of a millimeter. So, in the end, I am optimistic, but ... I can not say anything more.
The theory originated in the late sixties. And then, from 1970 to 1995, it became incredibly popular - all leading universities invited only physicists who understood it. I remember that at MIT (I was forty-three at the time), they also tried to take supporters of the theory — such was the peculiar fashion. But this does not diminish the importance of string theory.
VD: And what are the questions in astronomy or astrophysics ... you are mostly an astrophysicist?
Walter Lewin: Yes, that's right. I wrote my dissertation on nuclear physics — back in the Netherlands, and then I was invited to MIT for two years, and then half a year had not passed, as I became a professor. And here my sphere of interests completely changed: I abandoned the physics of the nucleus and switched to astrophysics. The fact is that at this time in astrophysics a whole new direction was opened - X-ray astronomy. It actually began in 1962, in June. I arrived at MIT in January 1966. X-ray astronomy was, so to speak, based in Cambridge, at the Massachusetts Institute of Technology, thanks to the joint work of MIT Professor Bruno Rossi and Riccardo Jacconi, who worked at the American Corporation for Science and Technology, then he was awarded the Nobel for it.
So, a new direction has appeared. I immediately grabbed him and became one of the pioneers. Almost everyone who joined this research in the sixty-sixth, can boast of this title. I was incredibly lucky to get into MIT in those two years and become a professor. All my publications after sixty-sixth were devoted to high-energy astrophysics: neutron stars, black holes and white dwarfs.
VD: Speaking of x-ray astronomy. Tell, please, for those who do not know what is so revolutionary about her?
Walter Lewin: Yes, I think I can explain.
Take the sun. The amount of X-ray radiation from it is a million times lower than the energy it emits in the optical spectrum. One millionth is very, very small, very small part, just tiny. If in the sixty-second year we placed the Sun at the star closest to us (it is about ten light-years away from us), we would not be able to fix X-rays from it or another similar object from Earth, there were not enough sensitive instruments. Even looking for X-rays from any stars other than the Sun was unthinkable. By the way, the first such proposal from the American Corporation for Science and Technology, NASA rejected. The reason: “C'mon, what kind of radiation do you want to find?” Just because if the Sun were ten light years away, we would not have fixed X-rays from it.
But still ... some objects were fixed. X-rays from them exceeded solar radiation by several orders of magnitude. These were completely new objects that scientists could not even conceive of until then. X-rays were easily detected throughout our galaxy, and in others too. It was all about fancy double systems - double stars. At the same time in such systems there was a flow of mass from a star with a burned-out core to an object of smaller size, probably, to a neutron star or a black hole. When a substance falls on a black hole or a neutron star, such a huge amount of gravitational potential energy is released that the temperature of the gas in the surrounding space rises by a dozen million degrees, and this hot gas emits X-rays.
Thus, we are talking about a powerful source of x-rays with a weak optical. Many of these objects were then impossible to see in the optical range, only in X-ray. Let me remind you again: our Sun from a distance of ten light-years can be seen only in the optical spectrum, but not in the X-ray one. So, X-ray astronomy changed the way we look at the universe, gave us a fundamentally new approach to astronomy.
VD: What questions of astrophysics and astronomy seem to you most interesting these days?
Walter Lewin: I think that not only me, but many astronomers and physicists would answer your question like this: we want to know what dark matter is. We want to know what dark energy is.
There are three types of energy in our Universe:
The first is the energy of which we, stars, galaxies and the planet, protons, neutrons and electrons are made of. We call it hadron matter. It accounts for only 5% of the total energy of the universe.
Another 27% is dark matter, and we do not know what it is. There is no doubt that it exists, but that this is a question.
68% is dark energy.
Just think: most of the universe is dark energy and dark matter. And we do not know, we have no idea what the 95% of the universe is. This is the future of research in physics and astrophysics. We will find out what is dark matter and dark energy.
VD: If we don’t know anything about them, are there ways to study dark energy and dark matter that give hope of success?
Walter Lewin: Yes. There are promising assumptions about so-called wimps . This, of course, is only a guess. But these weakly interacting massive particles can be attributed to dark matter. Their mass is ten to the hundredth degree greater than the mass of the proton, they have not yet been fixed, and they do not interact with the mass, with the baryon mass - this is the problem. We can not see them directly, only to fix indirectly. For example, to observe what effect they have on baryonic matter, on the stars of our galaxy, but it is impossible to directly detect them.
So, wimps are not capable of electromagnetic interaction, maybe we will never find them, if only in a roundabout way. However, these theories are developing, the particles are trying to detect. Maybe the Large Hadron Collider will find them once. In this area, I am not an expert, but the word "wimp" is worth remembering, and even googling - this will help to understand what they are thinking about dark matter.
VD: And maybe we will also find some video and translate it later.
You said, if dark matter is the same matter as usual, but different ...
Walter Lewin: Actually, it’s not from protons and neutrons. Therefore, we can not say that it is the same. There could be no stars out of dark matter ... People would not have come out of it, because we also consist of protons and neutrons. That is, it is something that can enter into a gravitational interaction, but consists of something else.
VD: But if gravitational interaction is possible for dark matter, can it somehow stick together, condense and form some objects?
Walter Lewin: This is possible.
VD: Is there any planet?
Walter Lewin: There is no planet. Planets reflect light. Dark matter is not.
VD: Well, some object ...
Walter Lewin: You are Newtonian. And I'm talking about protons and neutrons. When you see, for example, my hand or these glasses, they reflect the light. In other words, it is the interaction between protons and neutrons in molecules and electromagnetic radiation. And so dark energy is not capable of it. But it is capable of influencing star formation and the movement of stars in the galaxy: this is how we understand that it exists. Do not even think of blinding a planet out of it - no one knows what kind of matter it is. If observable objects could be formed from dark matter, it would also enter into electromagnetic interaction, which, as we know, it cannot. That is, you can not take the radar and reflect its signal from the dark matter. Neither radio signals, nor light, nor lasers can be used in this way.
VD: It turns out that dark matter is not at all like the one we are used to, and 95% ...
Walter Lewin: No, dark matter is about 27%. Dark energy is something around 70% if rounded.
VD: And we don't know anything about them. And besides that, what of the known and observed objects in the universe causes you the greatest interest?
Walter Lewin: For me, the most interesting objects, firstly, white dwarfs . I mention them first for a reason. In 1841, Bessel suggested that Sirius is a double star. In the sky we see only one, but he said that there are two stars. He declared it confidently, and here's why: if you look closely at the location of Sirius in relation to other stars, it turns out that he moves and describes a circle every fifty years. According to Bessel, this is possible only in the case of a double star. Here is a quote from a letter written by Bessel in the forty-first year - this is an important milestone in astronomy, so I will read it, translated into English:
“I adhere to the belief that Sirius is a double star system consisting of a visible and invisible star. There is no reason to believe that luminosity is a necessary property of a cosmic body. The observability of a myriad of stars is not enough reason to disprove a myriad of invisible stars. ”
Once again: "The observability of a myriad of stars is not enough reason to disprove a myriad of invisible stars." From this began the astronomy of the invisible.
In 1862, in Cambridge, Massachusetts, where I live, where MIT is located, Alwan Clark , son of a famous telescope manufacturer, tried his father’s new creation: an 18-inch refractor telescope. He aimed the lens at the Boston horizon, when Sirius rose in the east and then he saw that second star! Just his telescope at that time was more powerful than everyone else. Clark named the star Sirius B. Then ...
Now we know the temperature of the star, its size: about the size of the Earth, a temperature of about 8000 degrees. But the mass is approximately equal to the mass of the sun. This means that its density is a million times greater than that of water. It is a white dwarf, a million times denser than water. When these objects — white dwarfs — were only discovered, no one could believe that this could happen. Now everyone is accustomed, and we already know billions of similar stars, about the size of the Earth, about the same mass as the Sun, with a temperature of 10-20 thousand degrees and a density of a million times higher than water.
In 1967, a second incredible object was discovered in the sky - neutron stars . They were discovered by Jocelyn Bell , who at the time graduated from the magistracy. Her supervisor was Anthony Hewish. He recorded radio flashes in the sky , but there was no optical confirmation. Flashes appeared once in a whole thirty-three hundredths of a second from one particular place.
This, of course, was taken as a communication signal from extraterrestrial life. The object was named LGM-1 ( Little green men ) - “The Green Man Number One". The information was kept secret: if all this were true, the consequences would have been unimaginable. Then found another object, very similar to the first. He was called the "green man number two", but later the thought of the green men was dropped.
Now we know that these were neutron stars. And again, in mass, they are about the same as the Sun, but in size they no longer reach Earth: their radius is about twenty kilometers. The density is not in a million, but in ten to the fiftieth degree more than that of water. This means their density is a million billion. They consist almost exclusively of a substance that is usually found in the nuclei. Dimensions, remember, a couple of tens of kilometers. They rotate at a tremendous speed: for some, a full revolution takes about one and a half milliseconds. Can you imagine an object with a mass of the Sun and a radius of ten kilometers rotates around its axis once a second, and some - once every two milliseconds ?! Unimaginable! This is the second interesting object.
By the way, for them Anthony Hewish received the Nobel Prize in 1974. What a scandal then! The scandal due to the fact that Jocelyn received nothing. It is outrageous that this is exactly what was decided in Stockholm. Perhaps the reason was that she was just a master, but strictly speaking, it should not have affected the decision. Even worse, if the prize was not given, because she is just a woman, which also should not have influenced the decision. Previously, the Nobel Prize often ignored women. Now the situation has changed, but Jocelyn was definitely cheated ...
Now I will say about the third and even more strange subject of interest. It was opened in 1971. Astronomers who worked on optical telescopes observed a powerful X-ray source called the Swan X-1 . Paul Mirdin and Louis Webster, and apart from them Tom Bolton, found out that he is part of a double star, in which the mass flows from a burning star to a compact object. They concluded that with high probability, Cygnus X-1 is a black hole. Why did they decide that? - They calculated the mass of the object, and it turned out to be more than three times the mass of the Sun.
At that time, it was already known that neutron stars can not exceed the sun by a mass of more than three times - in this case, they collapse and turn into black holes. And so, black holes were opened. This is now a kind of astrophysics hit. The mass of black holes can be billions of times more than solar.
So, to summarize what I have told, the most interesting objects in the Universe are white dwarfs, neutron stars and black holes. Black holes are the very best of them, and I last mentioned them because I spoke in chronological order.
To work with a singularity, you need to deal with quantum gravity, so we can study black holes so far only with certain restrictions, and these restrictions are singularity. But neutron stars and white dwarfs are also nothing.
VD: What about mole holes?
Walter Lewin: Wormholes are still at the stage of assumptions.
This story began with a 1935 article. Einstein and Rosen suggested that it was possible to build a move from one space-time to another. The general theory of relativity refers precisely to space-time. And if it is possible, it is also possible to move back and forth in time, but this is not yet confirmed. The trouble with time travel is this. If someone moves, say, 60 years ago, he can kill his mother.
VD: Well, she would have been a child then, but ...
Walter Lewin: Well, fifty, then can I? And then this person would not be born. That's the problem. Although it has something to answer, and the answers are very mysterious. For example, a multiple universe appears here, an infinite number of our twins, and in one of the universes this man just was not born and did not kill his mother. But in general, time travel is a problematic issue.
VD: Since we are talking about things like time travel and other exciting activities, the question is: do you think the universe is infinite? And if not, then what is there, beyond the edge of the universe?
Walter Lewin: Good question. And the answer is: who knows? What we know is the size of the observable universe. Observed - that is, that part of it that we see through radiation. If objects move away from us at a speed greater than the speed of light, and this, I will tell you, perhaps, then we do not receive any energy from them - this is due to the Doppler redshift. If you look at the images of the so-called deep field of Hubble, you can see dim galaxies, the light from which went to us 13.5 billion light years. That is, we see where they were more than 13 billion light years ago - remember this thought.
However, the universe is expanding, and now the distance between us and these galaxies is already about 45 billion light years. It was 13.5, and now they have retired to another 32. There is no doubt about this - we know that the Universe is expanding.
Let these galaxies still emit something, but we can not fix it. We know that they exist, we know that they are removed at a speed of 2-3 times the speed of light. And thanks to them, we have a radius of the observable universe - about 45 billion light years. But we cannot see what is there, because the radiation is not enough for us. If you wait 10 or even 5 billion years and then look at those dim galaxies that we are seeing now, they will not be there anymore: they fly away from us at a speed greater than the speed of light. Not lost thought?
So, we take these galaxies, wait for 5 billion years and Hubble takes pictures of the same place ... And there is already nothing there. There will be other galaxies in that place, but those that we saw there will not, we will not see them.
We know nothing of what lies beyond the boundaries of the observable universe. Maybe there are other universes, maybe a sister universe, there may be hundreds of these universes, and hold on tight ... According to the concept of the multiverse, there may be not only a hundred, but an infinite number. And if there are an infinite number of them, then the universes have always existed. To create something of infinite size is impossible, unless our time is infinite. Here you can throw away the concept of creation, because the eternal can not be created at some point in time. This idea is not easy for us to realize, but if we have an infinite number of universes, then the universes should always exist, and no one created them.
But creation is an important concept for religious people. They need an eternal creator god who creates the universes. They need something eternal of such an order. And to us - no, our universe itself can be eternal and always be.
Surely it is too early to say, although such an opportunity fascinates those who think in Newtonian terms. I want to give one curious and difficult to understand example of infinity. Take an infinite number of monkeys, give them an infinite number of typewriters. Pressing random characters, some will type the complete works of Shakespeare. The letters will stand exactly in the order in which Shakespeare put them. This is the concept of infinity. We are not aware of the infinity. Whatever huge number you deduct from infinity ...
VD: ... infinity will remain. By the way, since you mentioned the creation and religious people. This question is probably asked every scientist. Do you believe in God? And how do you feel about the religious view of the world?
Walter Lewin: Well then. First, and this is a very important thing, everyone is free to believe what he wants. One must respect people of any belief, if they are not criminals, if their religion is peaceful — I follow this conviction. I repeat: everyone is free to believe what he believes, what he wants.
With science, the story is different. For science, only verified facts are important. In religion, they are not required. After all, if you believe in what you like, what's the difference if you can check it out. And yet I respect all religions. Freedom of religion is one of the pillars of democracy. In any democratic civilization, there must be respect for all religions. Therefore, what I believe in myself is not important. However, by conviction I am an atheist, this is my opinion. And yet, I respect those who believe in gods, and I hope they will show respect for me and my beliefs, because I, too, can believe in what I want — that is, adhere to atheism.
Respect for any belief, including atheism, is the cornerstone of any civilized democracy. If there is no such respect, then I have no respect for the country. Neither the country nor its leader. One thing is his religion, but one cannot respect the leader who imposes his religion on the whole country, this is terrible.
VD: And more about religion. If we talk about religious and scientific beliefs ... It seems that Neil Degrass Tyson said that it is possible to instill in children an interest in science, if you just leave them alone: after all, they are already curious, they are researchers anyway. Do you agree with this? Do you think that the scientific method, the scientific view of the life of children should be taught?
Walter Lewin: Well, I would not say that they need to be taught, but children, of course, can be instructed. When a child is about five years old, you can show them wonderful National Geographic programs, you can go with a child to a science museum, you can solve problems with them - I did this with my children - to show a problem or a problem that at first seems unsolvable until you think better. I think you need to direct them. And when they grow up, I would advise you to show them the programs of Neil DeGras Tyson or Brian Green, and your own videos.
So I would not leave them on their own, but if a child comes with a question, then you need to answer and push to ask new ones, encourage it. But I would not use the word "teach" here. I would say it is worth helping children naturally expand their horizons. Knowledge will not deprive you of anything, but will only add.
VD: Yes, it looks like mentoring fits better here, not learning. Since we have touched on the topic of training and instruction. You are one of the most legendary teachers, at least on YouTube. On the Internet, you are an endless sensation, and you have amazing lectures. And the question is this: have you ever thought about teaching at school? Guide the minds of young children?
Walter Lewin: Answer: definitely not. Because besides the fact that I am a born teacher (to be shy), I am also a born scientist. Having finished my dissertation in physics, I intended first of all to engage in scientific work, to investigate the unexplored, and X-ray astronomy fit perfectly well. So what is the choice: a schoolteacher or a MIT professor? Easy to decide.
And yet, I will tell you, having received a bachelor’s degree, I worked for five years in the Netherlands, in Delft, and besides scientific research, I taught physics for 20 hours a week in high school in Rotterdam. It was an unbearable burden.
Why did I do this? - I need to mention here the reasons. I did not teach for money. Five years of work as a teacher of physics and mathematics allowed not to go into the army. I escaped the call, but one more thing - the government gave me a huge research loan. And each year of work as a teacher reduced the amount that had to be returned by 20%.
VD: For five years.
Walter Lewin: Yes, there was such a time limit for payment. So, I have been teaching seniors for five years, but still not first graders. And believe me, I had a great influence on the students - just as I later influenced my students at MIT, and now millions of people thanks to lectures on the Internet. But I never taught 6-7 year olds in elementary school. For my own development, personal evolution, this would not be the most natural occupation.
VD: You said you are a teacher by nature. Does it mean that you never studied as a teacher? And you have your own approach, artistic and unique. Have you decided on your teaching style from the very beginning, or have you come to it gradually? Do you think your first and your last lecture are equally good?
Walter Lewin: No, of course not. See it. I am an eccentric person and it was clear already when I was 2-3 years old. If eccentricity is peculiar to you, non-standard thinking is also peculiar. Do you understand what I mean? This means that you are trying to do everything in your own way. As I was dressing up at a lecture at MIT, no one of the professors ever did anything else. Did I just try to please people with my clothes? - Of course not. Did I try to impress in this way? - And no again. I just - Walter Levine, I was always like that and dressed like that. I wore jewelry, bracelets or at least some brooch. Now I’m wearing rings, look how beautiful. I have thirty-five pieces in my collection. Those that are on me now, I bought in South America.
VD: Cool.
Walter Lewin:I do not try to stand out due to this, I myself am so. My lectures, even the lessons in that school, were already different from the usual ones. Whether they were better, let others decide. But from my own experience I can say that when you try to present material in a new way, you inspire people more. Students follow the lecture without blinking. This kind of art I developed all my life. Over the long years of teaching, I realized that even at MIT, it doesn’t matter how you present it, it’s important what you bring to the student. Think about what you're talking about, it doesn't matter. There are teachers who like to boast that they spoke with 12-year-old children about quantum physics, about the special theory of relativity. Yes, no matter what they said there. The main thing is that you bring it, and you can bring a love of physics. In people you can open a blazing fire and love for the world around them, the desire to understand it.
I make my students see through the equations, and most professors write equations on the blackboard and frighten students to numbness. Students think that physics is a solid equation, but that’s not true! I myself remember equations ten, that's all. In physics, understanding is important, the rest can be found. The concept of physics as a set of equations is fundamentally wrong. At lectures, as you probably noticed, I focus on demonstrations, I try to find something close to the real world in which students live. My goal is to show a rainbow, which they had never seen it, to make a new view of the clouds, a new look at the sky. So my teaching style is a completely different approach: my lectures are inspiring.
I gradually achieved that (I am not exaggerating now) that I can make people laugh when I want. I have a congenital sense of humor, jokes go off by themselves, I can make you listen to me with an open mouth, but at least forget that you need to breathe, I can make you cry, and, in fact, even wet your pants - and this is also not an exaggeration.
In other words, I found a way to improve my original talent. I once finished a lecture by giving out flowers to students. When we had just completed all four Maxwell equations, I decided to pompously mark the end of the topic of electricity and magnetism, to which I devoted the last ten minutes to the lecture. I called each of my students, and that’s 600 people, with 600 daffodils on their table. So here. About thirty years have passed since then. They forgot all the Maxwell equations, and the daffodils surely remember, like the connection between Maxwell's equations and these colors. This is my conceptual approach: they surely remember the importance of equations due to those daffodils. And if they need the Maxwell equations themselves, they will find them in five minutes.
The principle of my lectures: to show so that remember. If I explain the period of oscillation of a pendulum, a certain rope with a load, the mass of which is not important, which seems not very logical, I myself will be that cargo. You will forget this: the professor swings back and forth at the end of the pendulum and calculates the oscillation period with an accuracy of one hundredth of a second! Such is the explanation that there is no difference between the 15 kilogram load and Walter Levin himself. In my opinion, it is important to use all resources, even yourself, and take risks in order to keep the audience and, of course, to involve students to the maximum. Here is my secret.
Needless to say, over the years, and this is 43 years at MIT, I have honed my methods. Although I must say, in the last 15 years I have reached my limit and have changed a little. I would call my last lecture on physics, a farewell one, which you probably saw, the peak of success. I managed to turn it into a game, to capture the attention of people, and most importantly - to give them inspiration. There I showed the sunset, showed the blue skies, maybe there was a rainbow too, I don’t remember. But in general, this lecture shows what style of teaching I think is the best. It is necessary to plow up ... Here, as in art: a new, different view of the world is important. And I offer this new look at every opportunity, a new point of view. For example, I need to explain the law of Snell. The professor, who speaks about it, is in fact about the refraction of light and does not recall a rainbow, just crazy! After all, students will remember the rainbow for life! And in it is the essence of the law. And she is familiar to all. This is a new point of view. Tell people about the rainbow, and they will never forget the law of Snell. They may not memorize the corresponding equations, but an understanding of Snell's law is not going anywhere. I described my approach to teaching in the last chapter of the book “Through the Eyes of a Physicist”.
Such a presentation is a kind of new art and a new way of teaching. So I would say that in teaching I am a kind of pioneer.
They wrote to me, and still are writing, thousands of professors, that after me they began to apply the same methods.
VD: We have two more questions about how you teach. The first is about your famous pendulum experience. You raised the ball to the chin, and then let go. How many times have you done this in your career? About.
Walter Lewin: I can give a fairly accurate figure, because I show the focus with the pendulum in a single audience at MIT, which is designed for 700 students. Such lectures lasted only three days, but one after another, from 10 to 11 and from 11 to 12, it turns out, 6 times. There were also 8 lectures for Japanese television, there was this experience. Together with the others - 9 times. Last time I gave the same show at a farewell lecture at MIT. That is all with everything 10 times. Have you noticed how artistically I have furnished everything?
VD: Oh yes, noticed.
Walter Lewin: Convinced the audience that this ball would kill me.
VD: Well, you could have bruised yourself. In some videos, people try to repeat your experience and get the ball in the face.
Walter Lewin: Yes, and that is their mistake ...
VD: They push him.
Walter Lewin: There are two subtleties. Firstly, for me the ball will not hit, because I cling to the wall - I cling tightly, with my whole body. When I let go of the ball, I do not change positions. In some videos, the teacher allows the student to do the experience, and if you look closely, the student leans forward and not pressed against the wall. There is a video where the girl leans, if you look closely, she bent over ten centimeters, if not more. Deadly number! But that wouldn't happen to me.
And if I pushed the ball, look, if you hold your hands like this, then without pushing to let go of the ball is very easy. I pretend not, but take a look at my hands. That's how I hold the ball. See you But how I clean them.
VD: Ah, spread apart.
Walter Lewin:I keep the ball like this, I just have to remove my hands. I always let go of the zero speed ball. He does not pose any danger to me, but I convince students that the risks are complete: I tell them not to breathe, not to cough ... "If someone coughs, my hand trembles, and then I push the ball - the fatal ball, because the lecture will be the last. ” And they believe me. And hold their breath, are pressed into the chairs, and someone and pants wet. This is all - part of my production. This is all important, because no one will forget. This is the only thing that no one will forget. And always this picture will be associated with the conservation of energy. What I need. The ball will not soar above the place from where I let it go, let it go - and it returns there too. And by the way, every time he stops somewhere a centimeter from my chin - this is due to friction with the air. The air in the audience slows down the pendulum a little, it loses a bit of its energy. So the ball never touches even the skin, it stops a little earlier. I feel the movement of air when it flies, and I close my eyes, but this is also part of the show. I close my eyes and feel the ball approaching (precisely by the movement of air), wait a second, open my eyes and say: “I am still alive! Physics works! ”The New York Times publishes a quote of the day in the upper right corner of the second page. On December 19, 2007, they published an article about my lectures on the first page, and on the second page there was a phrase: “Physics works, and I'm still alive.” Funny, no one even knew that this was my phrase. but this is also part of the show. I close my eyes and feel the ball approaching (precisely by the movement of air), wait a second, open my eyes and say: “I am still alive! Physics works! ”The New York Times publishes a quote of the day in the upper right corner of the second page. On December 19, 2007, they published an article about my lectures on the first page, and on the second page there was a phrase: “Physics works, and I'm still alive.” Funny, no one even knew that this was my phrase. but this is also part of the show. I close my eyes and feel the ball approaching (precisely by the movement of air), wait a second, open my eyes and say: “I am still alive! Physics works! ”The New York Times publishes a quote of the day in the upper right corner of the second page. On December 19, 2007, they published an article about my lectures on the first page, and on the second page there was a phrase: “Physics works, and I'm still alive.” Funny, no one even knew that this was my phrase.
VD: Another question about your teaching style. Have you ever had problems with the university because of your methods? Here you have placed this pendulum in the audience, you arrange the whole show, you smoke right at the lecture to let in smoke and explain the topic. Have you had any problems with this? Has the university ever prevented you from teaching the way you want? Or did they say to you: “Oh, do it, as you know!”?
Walter Lewin: Well, you know, MIT is such a place ... this is paradise. Professors are allowed to do everything they want at lectures. I have always been supported and they are people of incredible professionalism. Together we organized just a huge number of different kinds of shows, sometimes we worked together, three of us, five of us.
Usually, the production plan is ready for me about three weeks before the lecture, we all discuss it in advance, sometimes they construct something for me, but more often, I don’t have to do anything about it. Smoking is an awkward story. I do not smoke. Last time I picked up a cigarette at thirty. Stupid, but I suffered from this habit from twenty to thirty years. Now I do not smoke. For that number I needed to inhale smoke. When you exhale, the smoke is white, and if you do not inhale it is blue. For the experience I needed to drag on once. During my career I did this fifteen times - one puff each. For 50 years to do 10-15 puffs is not so scary and not at all dangerous. Did you see this video? I first set fire to a cigarette there, she smokes, there is such a bluish smoke. Then I pass smoke through the lungs: water droplets are combined with smoke particles, their size increases,Rayleigh scattering , the light is reflected as usual - just this happens with the clouds, because of this they are white.
Waves in this case ... When Rayleigh radiation is visible blue. In other cases, any light is scattered equally, so the smoke from a cigarette appears white.
VD: Yes, that was your last lecture.
Walter Lewin: Such is the way of explanation. But in general it can be different. What is interesting ... In general, it is very important to add an element of humor. Students sometimes need to laugh. When I swing in place of the pendulum, have you seen the audience? Yes, they tear the bellies.
VD: Yes, I also had a lot of fun watching your lecture. So yes, it works. And what would you advise novice teachers? You have already said that you need to be passionate about yourself, you need to submit material in an interesting and fun way.
Walter Lewin: Well, in many respects it should be inherent in the personality of the teacher himself. People either cannot or can change their personality, but with great difficulty. Ideally, it is necessary to radiate love for your subject - it is contagious. We must radiate a love for students. They know that I love them, I can see it. If you use any opportunity to draw a parallel between their daily life and experience and their lectures, you can force them to share your view of the world.
There are professors who have no sense of humor at all. In the Dutch language for such a word came up, I will not say what, it is not the most decent.
VD: Nobody knows Dutch here, so if you want ...
Walter Lewin: Dutch is a very colorful word, I don’t know it in English.
In a sense, you have to be eccentric, but the main thing is passion. It is necessary to burn what you are telling. It is difficult, and it is hardly easy to learn. Just imagine, I will tell you or colleagues at MIT that preparing for one lecture usually takes from 60 to 80 hours: I do three full runs. The first rehearsal two weeks before class, I note the time and leave notes in the text - I never fit and have to change something. A week before the lecture I run it into an empty audience - it’s already clearer how to organize my 50 minutes. At six in the morning on the day of the lecture, I again come to a deserted audience and play all over again, as if I already have all the elements for my experiments, although they are not there. And yet I rehearse, including going to the door of the audience, when to turn on and off the light, precisely in order to correctly calculate the time. You can't delay students at MIT - they get up with a call, because they have to go to other lectures too. Therefore, you need to meet exactly 50 minutes. Take any of my lectures: they are from 49 to 51 minutes, not longer. I always have a very precise plan, and every 5 minutes I check my notes in a lecture with the hours on the table. If I’m behind for a minute, I’ll track it, if I’m two, I already know that I need to hurry, if I’m three, then that's all, I don’t catch up with time. So ... you can not force others to suffer so much. that you need to hurry, if for three, then all, not to catch up with time. So ... you can not force others to suffer so much. that you need to hurry, if for three, then all, not to catch up with time. So ... you can not force others to suffer so much.
If you take my colleagues from MIT ... Half of them are excellent teachers ... And many could prepare and show wonderful experiences that would take me 20 minutes. And they have 20 minutes, if you get right to the point, but they are not preparing. They look at the clock, see what is left 5 minutes, they will say: “Oh, time is short. Okay, I'll show you the experience, but there is no time to explain. ” This is a crime! How can you rush a visual demonstration of physics? We are not clowns who just show tricks. If this is the only way, it is a tragedy. Align time can only chase the entire lecture. I never lost more than a minute.
If it takes 20 minutes to show something (I assure you, it’s written in my plan that so much time is needed) - I always consider the remaining time, and never the other way round: at the beginning it costs 50 minutes, after 5 minutes I write 45 , after another 5 minutes - 40 minutes. That is, when I want to finish the experience and his explanation, there will be 20 minutes in front of him. Thus, I always fit in time, and never count down the opposite. So, I will always find these 20 minutes. Clearly, colleagues consider it insane.
VD: To some extent it is. On the other hand, that is why your lecture has the number of views and reached five or two ... up to several million - so many people saw them.
Walter Lewin: My farewell lecture has over six million views. And if you add up everything, you get about seven million views a year. So in three years my lectures have been watched twenty-one million times. But that same lecture, yes, more than six million is just my most popular lecture. I never thought it would be my most famous lecture.
VD: Unfortunately, our time is coming to an end, but I would like to ask you to briefly tell you about your favorite movies or books related to physics: artistic or non-fiction, maybe co-fiction ... which you would recommend to see to get into science and, in particular, physics.
Walter Lewin: I would recommend one book. This is a book by the Dutch professor Marcela Minnart , he worked in Utrecht. The book in Dutch was called “ De natuurkunde van 't vrije veld ”. “Natuurkunde” means “physics”, and “'t vrije veld” is “the world around”, not a room or a house, but what is outside. In his book, Minnart talks amazingly about rainbows, blue skies, white clouds.
For example, he tells how to calculate the size of the ripples on the water by the solar flare that you see on the surface of the reservoir. He teaches to look at the world as a physicist looks at him. This is probably the only book that made me start looking at it myself. I can even assume that if it were not for this book, my views would have developed in a completely different direction.
Minnart is the man who, metaphorically speaking, sowed the seed of interest in my head, and then I could only water it so that a sprout would break out of it.
There was not a single video, not a single film, which would have had an equally strong influence on me. Most videos, including Brian Green, and various space films, for me, give away cheap stuff. They simplify the explanation so much that it goes against the science. The first "Space Odyssey" was nothing, but when it comes to science, at least shout, of course.
Perhaps you can advise National Geographic - they show decent things. They do not simplify science to distortion. There are simplifications, but they do not lead to mistakes, which is also found in Brian Green, and in others. This is not a criticism, but still they try to be understood to reach errors that I don’t like.
There is still such a book ... a very important one ... and I read it once, and I still have it. It was written, it seems, by some Englishman ... A very famous book about science, by the way. I do not remember the name of the author. Maybe even some Russian wrote.
It's a shame that I do not remember the name of the author. But this is the second most important book about what science is. Usinov? Usinov seems to be something like that. Do you know this? I apologize that I have problems with memory, so I can not remember the author.
VD: And, probably, the last question, but one of the most interesting. If you could ask a question about the Universe and are guaranteed to receive an answer, what would you ask?
Walter Lewin: What is dark energy.
VD: Just like that?
Walter Lewin: Yes, of course. This is 70%. I would not ask about dark matter, because its only 27%.
VD: Well, and you can't argue ... Well, it seems to us it's time to finish. Thank you very much, and maybe you would like to say something to the subscribers of our group, our channel for which we translated your lecture and several interviews.
We are watched by students, boys, girls, adults, many who. What would you say to a Russian audience that is keen on science?
Walter Lewin: Constantly study. Knowledge takes nothing, only adds. It concerns anything. Be it art or science, biology, or repairing a flowing tap. Knowledge only adds, so learn. Try to study art especially. People usually consider art what they like, and do not consider what they don’t like. This is a fundamental mistake. He who knows nothing about the history of art will not understand what a breakthrough in art is. This requires knowledge. The same is true for physics. So: learn.
It was a transcript of a video interview with Walter Levin.
Record with translation into Russian:
We also attach the original version of the interview, without translation:
February 6, 2018 Walter Levine received our package with the publication of his book in Russian and sends his regards to everyone!
