Which Way is Our Earth Rotating?

Last month, I had a chance to teach college students in an Environmental Sciences for Liberal Art Students course. Almost all of the students were planning on becoming teachers themselves. One of the opening activities I did was marking the shadow of a lamp post and then coming back ten minutes later and seeing that the shadow was now in a different position. I mentioned that we are taught somewhere in grade school that the explanation for this is that the Earth is turning but that most of us have put that in our brain as an explanation but never really connected it to our actual experience. So based on the two marks of the lamp post’s shadow, which way is our planet actually rotating?

Most of the students started with their mental map of the world and tried fitting the shadow into it – instead of starting with the phenomenon. So there were lots of different opinions. I went with this diversity and encouraged discussion with different groups presenting their explanation and then sending them back to the phenomenon again. It took around twenty minutes for the group to come to agreement on which way we are rotating.

The students write reflections after each class and the instructor sent me copies of their reflection of this class. This shadow activity figured prominently in their reflections. The general tone of their reflections was nicely expressed by one student as, “I have never had a teacher not give me the answer to something before, unless it was a test, which this wasn’t!”

We tend to teach the way we were taught, so teacher telling tends to lead to more teacher telling. There is nothing wrong with teacher telling. And there could be an institutional feeling that if I am being paid to educate these students, then I have an obligation to be giving them the answers to as many things as possible. But taking in, on authority, and memorizing well-organized material is a very different intellectual skill than creating understanding from raw experience. Both are valuable but the latter is important in a culture where all sorts of interest groups are packaging their ideas in well-organized forms that they hope will be easily taken in. I am still amazed at how naively unaware I went through sixteen years of education. Not until two weeks before college graduation did I realize I was totally clueless about what I was supposed to do with this education – and took me another year to start figuring it out.

The difference between these two skills remind me of an anecdote from Surely You’re Joking, Mr. Feynman! in which the physicist, Richard Feynmann, first saw the cyclotron at Princeton, the graduate school he had chosen. His undergraduate college had a brand new cyclotron that filled an entire room and that had an adjoining control room. But the cyclotron at this graduate school was a mess. “In this room there were wires strung all over the place! Switches were hanging from the wires, cooling water was dripping from the valves, the room was full of stuff, all out in the open. Tables piled with tools were everywhere; it was the most godawful mess you ever saw…. I suddenly realized why Princeton was getting results. They were working with the instrument. They built the instrument; they knew where everything was, they knew how everything worked, there was no engineer involved except maybe he was working there too…. It was wonderful! Because they worked with it. They didn’t have to sit in another room and push buttons.”