Some of my favorite online videos are physics lectures by Walter Lewin of MIT. 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. Not necessarily relativity, maybe, or about all the weird sub-particles beyond protons, neutrons and electrons. But it would be great if people knew what Newton knew and other physicists knew up to around the year 1890. Then you can understand why things orbit and fall, and what’s going on when two cars crash. A little bit of physics goes a long way in helping you understand a huge number of things.
Lewin believes that all science, even theoretical physics, is ultimately experimental. That’s why he’s skeptical of ideas like string theory, which do not yield experimental predictions. I wish more people shared Lewin’s appreciation for observation, measurement and data—especially in debates over incredibly important matters that concern me very much, like public finance, climate change, education reform and vaccinations. In our foundation’s work, we try hard to make sure that our efforts are based on good data and subject to rigorous evaluations based on the evidence. The data sometimes surprises or disappoints us, but we need to confront it if we’re going to have any chance of being successful in the long run.
Lewin is an inspiring example of a scientist who is dedicated to careful observation, measurement and experimentation, the most reliable routes to real knowledge. He is unique, but we all can learn a lot—about teaching and life, as well as physics—from him, his lectures and For the Love of Physics.