** I'm writing this post as a way to try to get to the heart of what bothers me about a video I watched. I am fessing up right away that the video bothered me somewhat on an intuitive and emotional level, and that this exploration is an unrefined and exploratory attempt to turn that intuition and emotion into words. Here goes. **
In a prior post, I discussed my views on the common student misconception about the seasons. In that post, I discuss why I prefer my students to have a well-articulated and personal misconception over an impoverished and authoritative correct answer. I also present in that post an alternative question that I have found to be MUCH more generative for learning and much less about exposing ignorance. I turned the question, "What causes the seasons?" into "Why in Maine is sun out for 16 hours in the summer and 8 hours in the winter?" My experience has led me to believe that this first question can set up a classroom dynamic of "expose and shame", while this second question can set up a classroom dynamic of "intrique and pursue". I'm not saying that the question alone does this, but that it helps put either the teacher or the students in a different frame of mind, which I can help sustain.
In a recent series of video (first and second), Veritasium asks passers-by the question, "Why does the earth spin?"
** Now, before you watch the videos, I want you to stop here, and ask yourself the following question: Do you think the above question is more likely to be an "expose and shame" type question or an "intrique and pursue" type question. Why do you think so? After you think about it, feel free to watch the videos if you want, but you don't need to.**
In the video, a common response from passers-by is that there is a force keeping the earth spinning–gravity, centripetal acceleration, something from the core. Veritasium states several times (to the youtube audience) that there is no force keeping the earth spinning. It is only inertia. The earth is spinning because the dust it was made from was simply spinning before hand. Fair enough. Veritasium's is trying to point to the idea that things in motion tend to stay in motion–the earth has been rotating and will keep rotating.
Aside: After seeing the video, Andy Rundquist and I began discussing with Veritasium on twitter why it might make sense to say force is involved in turning the earth. I'll argue that forces are, in fact, involved in TURNING the earth–included in these forces are gravitational forces and inter-molecular forces. Those forces act in concert to generate centripetal forces. While they ARE NOT involved in maintaining the speed of the spin, they ARE definitely involved in maintaining the turn. Each piece of the earth turns, exactly because there are net forces that turn those pieces. So the blanket statement: "There is no force" is kind of well, wrong, at least a little bit. To take this even farther, these inward forces WERE actually involved in how the earth got to its present speed, because as all that dust moved closer (decreasing its potential energy) together each piece increased its kinetic energy. So in some sense, gravity was the cause (not of the spin), but of how the earth got up to its current rate of spinning. Taking this even further, the earth is now SLOWING down. It is slowing down for much of the same reasons that objects on earth start slowing down--the earth interacts with other objects in the universe. Without going into details, the earth is slowing down as the moon moves away from the earth--this is like the opposite of when the dust was collapsing in causing the spinning rate to increase. With the moon moving away, there is an increase in gravitational potentiel energy, associated, in part, by the loss of the earth's rotational kinetic energy.
My point isn't to shame Veritasium on his physics. He is a sharp guy that knows a lot of physics. My physics is probably wrong, incomplete, and misleading in some way. My point, however, is to emphasize how simple-authoritative answers to complex and intriguing phenomena often lead to impoverished understandings in science and of science. My second point is that how we talk with people, including the questions we ask, establish the kind of science we invite them to participate in.
When I see Veritasium's video, I see evidence of people who have been victims of a life time of "impoverished-science-answer-give-a-ways." My evidence being the amount of science jargon being throw out–centripetal forces, law of inertia, equal and opposite forces. At on point, Veritasium micro-shames one person for thinking that inertia is a force. At another point in the video, a student just starts throwing out words, "velocity, rotation, speed, spinning, moving". Veritasium wants the kid to say, "acceleration," and even at one point says to the kid that he is so close. This kind of interaction is no different than what this student probably experienced in school where the teacher had a correct answer in mind and the kid was supposed to guess that answer. Another kid at another time makes the right observation (that forces causes change in speed) and he immediately validates his right answer with a high five as says, "you are nailing this." This is just like science class as well–quickly validate the right answer.
Now, once again, my problem with the question and the video isn't so much that the physics answer is a little big wrong or perhaps incomplete or misleading. My issue is more that the question and the situation is designed to expose ignorance rather than to generate learning or foster intrique or promote inquiry. Now, to be fair, we do see some forms of inquiry going on. People are grabbing this sphere and trying to speed it up or slow it down. People are pondering a bit about how things work. But the interviewer, ultimately keeps steering that inquiry toward a "expose and shame" kind of interaction and steering the conversation toward "say the right words" kinds of interaction. The best inquiry I see happens with the little kids--this is probably not a coincidence. They haven't yet been victims of a lifetime of teachers and scientists talking to them about science in a way that is about "expose and shame" and "say right words to get validated".
I would probably not ask my students the question, "Why does the earth spin?" I might ask instead, "Why doesn't the earth seem to be slowing down in the way that spinning objects on earth seem to?" I might ask, "Do you think the earth has always been spinning at the same rate? What would make it speed up, slow down, or stay the same rate?" I'm not convinced that these questions, in and of themselves, would be much better. But I do think that the question would position me and my students to be more attuned to and expressive of tentative hypotheses and authentic explanations over vocabulary and authoritative handy-downs.
Now, granted, I enjoy watching Veritasium's videos. I will continue to watch them and continue to enjoy them. But if I don't try to uncover the source of my uneasy feeling about them, then I'm not growing from that experience. Here's to growth