Some of my favorite online videos are physics lectures by Walter Lewin of MIT. They’re posted at MIT OpenCourseWare and Academic Earth, and they’re brilliant. Lewin is an incredible teacher who’s passionate about the beauty of physics and its power as a way of looking at the world. He really brings science to life. One of his famous classroom demonstrations, which is on video, involves a pendulum that you think is going to hit him and hurt him, but because it’s slowly losing momentum it never quite touches him, although it comes so close that it’s a bit scary.
Part of what makes Lewin a great teacher is that he has a lot of energy and enthusiasm, and fun ways of explaining things. If he ever explains something the wrong way on his videos and a viewer catches it, even a small mistake, Lewin inserts a little video pointing out his error -- he has a nice way of saying "oops" about things.
He began teaching when he was very young at a school his parents ran in the Netherlands, a school that taught business skills. When he got to MIT, he put a lot of his energy and enthusiasm into an introductory physics course. It’s famous for his demonstrations, which raise questions, which lead to more demonstrations, which lead to answers and equations – instead of starting with the equations.
Lewin’s teaching skills come through in his wonderful book, For the Love of Physics, which is good even if you don't know much physics. He'll introduce a mystery and then show how you can understand it with just a little bit of physics. He helps you appreciate that physics is pretty basic stuff. Like, what is metal? What is it good at? Why can we build big buildings today and cars and planes, but hundreds of years ago they couldn't do that stuff? Why are there stars and what's going on in a star? And why can phones work? Wireless phones? And what is a microchip, what's going on there?
Fortunately, if you understand just a few physics concepts, like electromagnetism and gravity, you can understand a lot, like how a global positioning system works, or how a DVD can store a movie. That’s why everybody should know some physics.