CAMBRIDGE, Mass. — Walter H. G. Lewin, 71, a physics professor, has long had a cult following at M.I.T. And he has now emerged as an international Internet guru, thanks to the global classroom the institute created to spread knowledge through cyberspace.

Professor Lewin’s videotaped physics lectures, free online on the OpenCourseWare of the Massachusetts Institute of Technology, have won him devotees across the country and beyond who stuff his e-mail in-box with praise.

In his lectures at ocw.mit.edu, Professor Lewin beats a student with cat fur to demonstrate electrostatics. Wearing shorts, sandals with socks and a pith helmet — nerd safari garb — he fires a cannon loaded with a golf ball at a stuffed monkey wearing a bulletproof vest to demonstrate the trajectories of objects in free fall.

He rides a fire-extinguisher-propelled tricycle across his classroom to show how a rocket lifts off.

He was No. 1 on the most downloaded list at iTunes U for a while, but that lineup constantly evolves. The stars this week included Hubert Dreyfus, a philosophy professor at the University of California, Berkeley, and Leonard Susskind, a professor of quantum mechanics at Stanford.

“We have here the mother of all pendulums!” he declares, hoisting his 6-foot-2, 170-pound self on a 30-pound steel ball attached to a pendulum hanging from the ceiling. He swings across the stage, holding himself nearly horizontal as his hair blows in the breeze he created.

The point: that a period of a pendulum is independent of the mass — the steel ball, plus one professor — hanging from it.

“Physics works!” Professor Lewin shouts, as the classroom explodes in cheers.

Professor Lewin revels in his fan mail and in the idea that he is spreading the love of physics. “Teaching is my life,” he said.

The professor, who is from the Netherlands, said that teaching a required course in introductory physics to M.I.T. students made him realize “that what really counts is to make them love physics, to make them love science.”

He said he spent 25 hours preparing each new lecture, choreographing every detail and stripping out every extra sentence.

“Clarity is the word,” he said.

Fun also matters. In another lecture on pendulums, he stands back against the wall, holding a steel ball at the end of a pendulum just beneath his chin. He has just demonstrated how potential energy turns into kinetic energy by sending the ball flying across the stage, shattering a pane of glass he had bolted to the wall.

Now he will demonstrate the conservation of energy.

“I am such a strong believer in the conservation of energy that I am willing to risk my life for it,” he says. “If I am wrong, then this will be my last lecture.”

He closes his eyes, and releases the ball. It flies back and forth, stopping just short of his chin.

“Physics works!” Professor Lewin shouts. “And I’m still alive!”

(For entire article go to http://www.nytimes.com -- December 19, 2007-- education)


TranslatorDec 19, 2007 @ 21:12