Lewin gives final lecture In emotional goodbye, physics prof. wows 26-100

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Lewin emotionally announces that this lecture is his last.
Manohar Srikanth—The Tech
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Illustration by Jennifer Hope
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Meng Heng Touch—The Tech
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Lewin signed copies of his newly published book after his last lecture.
Ana Lyons—The Tech
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The 75-year-old Professor Lewin takes 10 full swings on a pendulum to demonstrate that adding mass will not change its frequency.
Manohar Srikanth—The Tech
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Lewin demonstrates Rayleigh scattering by showing that cigarette smoke scatters blue light.
Manohar Srikanth—The Tech
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Lewin lights the third of four cigarettes he needs to generate enough small particles to demonstrate Rayleigh scattering.
Manohar Srikanth—The Tech

With a crown of tousled grey hair on his head, a shroud of rainbow-stripes on his shoulders, and a large plastic fuchsia ring twisting around his left middle finger, legendary physics professor Walter H. G. Lewin set down his piece of dull yellow chalk for the last time, marking the completion of his final lecture at MIT.

This was not something new for Lewin. Since 1972, the professor emeritus has stood in front of crowds of students, in this exact room (26-100), to deliver decades of lectures in MIT’s Mechanics (8.01), Electricity and Magnetism (8.02), and Vibrations and Waves (8.03) courses.

Like in many of his famous lectures, Lewin performed a dazzling array of demonstrations jammed into 47 minutes — including a giant pendulum, on which he rode and broke a sheet of glass; a demonstration of light diffraction via cigarette smoke (which Lewin lit and smoked himself); and the creation of a “red sunset” on the projector screen, to demonstrate the polarization of light.

But this time — on May 16, 2011 — a blanket of tears coated his bright blue eyes, and Lewin walked across the stage of MIT’s largest lecture hall to address the crowd.

“I have given, in this lecture hall, about 800 lectures. And it is wonderful to be back here, but it really hurts to know that this is my last lecture in 26-100,” he said. “I have therefore decided that I want to leave you in style. The way I will do this, is I will leave 26-100 in my own private rocket.”

Off to the side, Lewin promptly grasped his cherry-red three-wheel vintage bike, sat down, and released the tab on a canister of CO2, which propelled him across the speckled floor of the lecture hall’s stage.

The room — overflowing not only with students, but also older alumni and their children — promptly stood for a standing ovation.

Lewin’s final lecture was given to commemorate decades of teaching at MIT, as well as the release of his new book, For the Love of Physics: from the End of the Rainbow to the Edge of Time — A Journey Through the Wonders of Physics (Free Press).

A native of the Netherlands and a professor at MIT since 1966, this astrophysicist and lover of art has been recently recognized for the high merit of his video lectures on MIT OpenCouseWare (OCW); this past March, Lewin received the inaugural Educator Award for OpenCourseWare Excellence (ACE).

Since their release on OCW and YouTube, Lewin says his lectures are watched by 6000 people per day, or about 2 million per year. Bill Gates has personally written to him, saying he has watched all 94 of the uploaded lectures. His last lecture can be viewed in full at

The Interview

To further commemorate Lewin’s efforts at MIT as a professor and educator-at-large, The Tech sat down with him to probe deeper into what makes this physicist tick, how he got to where he is today, and what his thoughts are on teaching, science, and even his first love: art.

The Tech: What inspired you to become a physicist?

Walter H. G. Lewin: My becoming a physicist was, in a way, a negative choice. In high school, I was very good in math, and reasonably good in sciences — that was, chemistry and physics, and I was OK in biology. I couldn’t see myself doing math for the rest of my life. It was clear that I was going to university, but math … no.

Well, then I was looking at chemistry, and my god, chemistry — you have to remember so many things. Which is not the case with physics. Physics is way more conceptual than chemistry. So it scared the hell out of me. And biology has the same problem. It is amazing what biologist have to know; the number of diseases — they even know how to pronounce them — and all the medications that they give. It’s just mind boggling. I would have been a complete failure.

So what was left over? Physics. That’s what I meant by negative choice. But little did I know that I was made for physics, and physics was made for me. So it just worked out so wonderfully.

TT: What do you think distinguishes physics from the other sciences?

Lewin: Physics is at the bottom of all other sciences. Physics is at the heart of everything. And it’s not because I want to brag about physics. Really, I have no interest in that. I’m not trying to sell you to become a physicist, really.

But chemistry, when you really think about it: Why does H20 exist? That’s physics! Biology: Why do certain microamperes go around in your brain? Why is your heart pumping? That’s physics.

Now you may give it a different name. You may call it “physical chemistry” or “physical medicine,” but it’s all physics. So, it is at the heart of everything.

That’s not the reason, per se, that I like it so much, but it is at the heart of everything. So it was exactly the right choice for me. Because it’s conceptually way easier for me, than to remember so much.

TT: What did your parents do, and did they encourage you to become a scientist?

Lewin: You should read chapter one of my book, to really understand this. But to explain some, my father was a Jew and half my family was gassed in Auschwitz. The war, it ended some 65 years ago, [but] the impact of the war will never go away. It is with me every day. Every single day. The war is with me.

So my whole childhood, and even my adulthood, is still in a way attached to that war. My father survived that war, luckily, even though he was Jewish.

Did my parents encourage me? Yes, but not per se to go into physics. They left that choice up to me. But they were always very supportive. I don’t think they were particularly proud that I did physics, but yes, they were supportive.

But I do remember when I got my PhD in physics, my father was proud. He then became proud of me, I think, because he was largely self-educated. So he did not ever make it to those top schools, and he didn’t even apply to them. Two generations back, going to university [was extremely uncommon].

My father said, ”I never achieved any title that had any respect, and my son did.” And when I became a professor at MIT, of course, he was glowing.

TT: When is it that you think you discovered your passion for teaching?

Lewin: I was always very interested in art history. Already when I was 11 years old, I would go every week to museums. I started to prepare talks on the various movements in art history, and I gave one talk, I remember, when I was 15 years old at my school about Van Gogh. Those talks were always extremely well-received. My discipline of preparing talks is so thorough — already then — that the talks were always well-received.

Then when I got what [Americans] call the bachelor’s degree, I was entitled to be a teacher at one of the top two [secondary] schools [in the Netherlands]. I could teach them math and physics, and I did that for three reasons. If you did that for five years, you did not have to serve in the army. Then every year [I] did that, 20 percent of my student loan was waived by the government. And the third one was, if I was willing to work 85 hours a week, I was able to get my PhD. So I was [killing] three birds with one stone.

However, the energy that that took was unbelievable, as I needed 22 hours teaching per week. But I did that, and that’s when I started to be a real teacher. And the students loved me, so at MIT, it was just a natural continuation of something that I loved to do. People love to do the things that they’re good at. It’s a natural combination. So I loved to teach.

TT: Do you remember the first course, or even lecture, you taught here?

Lewin: At MIT, my first lecture was 1972 8.03 (Vibrations and Waves), which did not nearly have the quality that my 2004-2005 lectures did.

TT: When did you start doing the demonstrations that you are so famous for in your lectures today?

Lewin: Day one, of course. I’d have to look at my lecture notes. I’ve added some. I’ve improved some. But surely from day one that I lectured here, demonstrations were key support to my lectures. I worked with the demonstration group day and night. The demonstrations, they have to work. So I do dry runs two weeks before the lecture, and then the morning of the lecture, I dry run, all of them.

TT: What do you think is the relationship between your inspiration for teaching and your inspiration for research? Do you feel your passion for teaching at all inspired your research?

Lewin: My research was very specialized. I did high energy astrophysics, measuring x-rays from the universe. There was no inspiration; it was the other way around. I would say, it was because I was doing this research that whenever there was an opportunity — the moment that the conservation of energy was discussed — I would introduce the collapse of super massive stars into neutron stars, and I would calculate in class the spin rate of those neutron stars. And then the moment we talk about Doppler shift, I would teach on cosmology. Whenever I can, I introduce examples from the real world and some that are inspiring to the students.

TT: How do you prepare your lectures?

Lewin: When I teach, I am completely obsessed with it. When I lecture, I am entranced. I dry run it so many times, it becomes a performance. It is almost as if I am watching myself.

I think of a lecture as having a structure that I call a house. You build a house that has a certain structure, and that is the way that I build my lectures. So when you remove parts, you have to make sure that you don’t remove a supporting structure in the house that will make the whole house collapse.

And in all the lectures that I’ve given, let’s say 1000, I’ve finished in plus or minus two minutes of the time that I had. The one time I abused the time, is when I went to 52 minutes [in a 50 minute lecture]. The room was dark with slides, so the students couldn’t look at their watches and leave. How I do this, is if you look at my lecture notes, I have marked every five minutes where I should be. And then if I’m a minute behind or three minutes behind, I can correct for that.

I’ll tell you another secret: My timers never go up in time; they only go down in time. There’s a reason for that. My lecture notes count down to zero, so I always know how much more I have. It’s very psychologically important.

TT: Regarding your work with OpenCourseware, why do you think education is so important?

Lewin: Educating the world! We are an ivory tower, and OCW has opened the doors. We were a forbidden city, where people only came and took pictures in the infinite hall. Now they can look at what we’re teaching! It’s brilliant! It’s the best thing since sliced bread! It’s truly incredible, and technology has made that possible.

MIT was the first to do this, and my lectures were the first to go onto OCW. Dick Larson really should get credit for making sure these lectures of mine were videotaped.

TT: Do you have any especially memorable fan mail from OCW viewers, from around the world?

Lewin: I have a file of at least a thousand letters that are so special to me that I save them. They are so enormously moving: people who tell me that I have changed their lives, people who tell me that I have made them see the world in a completely different way. Some people write me saying, “Professor Lewin, I hated physics, and now I love it.” Oh man, every day. So I have this huge file of letters. It could almost be issued as a book, except for confidentially issues.

TT: What are some of the countries you hear from?

Lewin: Lots from India. Japan. South America. Australia. Europe. China. Almost any country that has connection to internet. That really is the limiting factor. Even these very poor areas in Bangladesh, I have at least 5–6 letters.

TT: What is the age range of viewers you receive fan mail from?

Lewin: Ten years to 95.

TT: What prompted you to publish a book?

Lewin: Well, I had a [front-page article written about my lectures] in The New York Times. And within about 48 hours, I got 25 publishers who called me. When the publisher comes to you, you do it.

TT: Do you have a favorite chapter in your book?

Lewin: The first and the last. You’ll have to read it to see. But the last one, I’ll just tell you, it’s about the new way of seeing. And that connects physics with art. And since both art and physics are both my love, my life … I have 125 works of art … I talk about how art is a new way of seeing, like physics.

TT: As a last, related question, what are the parallels that you see between science and art, in terms of ways of seeing?

Lewin: The parallel is that pioneering art and pioneering physics break new ground. They make us look at the word in a different way. But you have to stress the word pioneering. That’s what they have in common.

Pioneering physics or any physics theory can be right or wrong. Art cannot be right or wrong; it can be good or bad. So it’s a totally different criteria by which art is being evaluated. But what they really have in common is that pioneering art makes you see the world in different ways.

Think of the impressionists, who at the time were considered idiots. At the time, it was considered that they couldn’t paint. Well, people who were completely uneducated in art had Monet on their wall. And they loved it. Van Gogh sold in his life one painting. He couldn’t give them away. People rip their pants nowadays for Van Gogh. His paintings now go for $60 million, because the world that he created is now part of your world. You accept that. They have made you; they have changed you. And the same is true of pioneering physics.

Think of Newton in the 17th century, of how he changed the whole concept of science. He changed fundamentally from an Aristotelian idea … to a field that can all of the sudden be calculated, and be measured, and can be verified. He can make predictions. And these predications could be checked. He changed the whole way we look at the world. Think about Maxwell. His equations. Think then about cosmology. And Einstein. Special Relativity. General Relativity. The whole world has changed after them.