Monday, December 26, 2011
Finding and communicating wonder in physics
Back in junior year of high school my first physics teacher, Mr. Rankin, proclaimed that:
“Physics is fun, ‘cause you get to play.”
On the new books shelf in the Boise public library I just found Professor Walter Lewin’s recent book, For the Love of Physics. As the promo video shows, he communicated his sense of wonder to university students at MIT. A hundred of his lectures have been posted on YouTube, written about in the New York Times, and currently are being viewed by about 6000 people per day from around the world. There is a marvelous one-hour video showing him discussing several topics.
One is the above equation describing the period of a pendulum. Professor Lewin shows his audience a long pendulum, like a cannon ball suspended from the ceiling of the lecture hall. First he demonstrates that the period doesn’t change when you swing the pendulum five or ten degrees from vertical. Then he shows that it also doesn’t depend on the mass of the pendulum - becoming part of the experiment by riding that cannon ball. He also uses that pendulum to discuss the conservation of energy, and the topic of demolishing buildings with wrecking balls.
In my senior year of high school, I recall checking that same equation by hanging a fifty-foot pendulum in a four-story tall stairwell. Back in our Advanced Placement physics classroom, we also proclaimed that physics works.
During the answers to questions at the 57-minute mark in the longer video, Professor Lewin reveals that it took him forty to sixty hours to prepare for each lecture. He did three full-length rehearsals (or dry runs) - one two weeks before, one a week before, and one at 5:30 AM the morning before doing those 10 AM and 11 AM lectures. However, for the book signing lecture he did six full rehearsals!