For the past four minutes, Walter Lewin has been laboring at the chalkboard, bent on conveying a point—or rather, a series of small, swift points, so close together they resemble a perforation. The 76 ...

While teaching large physics lectures at MIT, Walter H. G. Lewin radiates enthusiasm. "And now, I’m going to blow your mind," said Lewin before giving a lesson about electrical circuits that seem to ...