He swings around a college lecture hall on a long rope to show how pendulums work. He demonstrates velocity by firing a rifle. Massachusetts Institute of Technology Prof. Walter Lewin has become a global Internet star now that anyone with access to a computer can watch his tough but fun Physics 1, 2, and 3 lectures free of charge. They can even do the homework he assigns his Cambridge techie students (though they won't get the grades or credit). The Netherlands-born Lewin, 71, told U.S.News's Kim Clark that putting his courses online took a lot of work and cost about $100,000—but was worth it.
Now that your lectures have already been recorded, do you think it's necessary to give them in person anymore?
I hope I will be doing [Physics 3] again this year. The students might as well just watch my lectures on the Web, but they will come anyhow because they want to see me.... But many other physics professors [at other colleges] use these lectures as their physics course, which is perfectly fine. They write me notes, saying "Why should we prepare lectures when we cannot compete with the quality of your lectures? We show them in class and use them as a starting point to have discussions with the students," which I think makes sense. But at MIT, we could not do that.... It's a tradition. There has to be a live person in the lecture hall.
Have you watched any of the other online courses?
I think Professor [Gilbert] Strang [whose Linear Algebra is also atop MIT’s most-viewed lists] is doing a very good job lecturing mathematics.
Is there anything you would want to tell other professors about how they can liven up their classrooms?
No one likes to be told how they should teach. But for each one of my lectures, I dry-run them three times. Once about 10 days before I give the lecture. Then about three or four days before. Then I dry-run at 6 in the morning of the day that I give the lecture. So it is like a performance, whereby I cannot even go wrong [with the demonstrations] anymore, even if I tried. Many professors, they have prepared the night before. They start giving their lectures, and they run into time trouble because they haven't done a proper timing. I know to the minute accuracy, where I am, where I should be, and never get into trouble.
In the lectures that are online, you often dress very comfortably—you wear socks and sandals. Did the tapings make you think about the way you dressed?
Well, I dress the way I like to dress. It's not that I say in the morning, "ok, now I have a video and so now I'm going to wear a tie." I don't even think I have a tie. But what I did at the time [I was recording the lectures] was, I was often watching the news to see what the narrators were wearing in terms of the design of the fabric.
MIT says its free courses don't offer access to its professors; you've been contacted by fans around the world.
I have about a thousand E-mails, and some of them make me cry, because they are so immensely moving. There was an incredibly moving one from an Iraqi, who said, "Look, you know, your country invaded my beloved Iraq, but we love you, Walter Lewin, we love MIT, so we must love the United States." I mean, that's an incredible statement.
You're 71. How long do you think you'll keep teaching?
As long as I'm healthy, mentally and physically. I will teach until I die in the classroom.