Life Lessons

Here are some "Life Lessons" I would like my students to learn:

• They have wonderful ideas and thoughts that are worth sharing
• They are smart and capable people who can learn anything
• Learning enriches life in both practical and aesthetic ways
• Meaningful learning often takes time and typically happens in concert with others
• They live in communities that are filled with other smart and capable people
• Responsibility involves acting in ways as to maintain or enhance one's community

How about you? What's your list?

Why my students should do assignments

I want students to put in significant intellectual effort into assignments outside of class. It would be nice if they choose to do so for one or more of the following reasons:

• They have come to feel a sense of responsibility to the classroom as a learning community.
• They have found out that their own personal experience in class is greatly enhanced when they put in work outside of class.
• They are intrigued, interested, or excited about some substantive aspect of the assignment, the topic, or the class.
• They have come to trust (based on their experience with me) that what I ask them to do has or will have value, even if that value isn't immediately obvious to them.
• They have come to value the attention and feedback they will receive from me and how this feedback contributes to their growth as a person
  
• They value the learning and awareness of self that comes with doing the work

I want them to be driven by a sense of responsibility to community (not to authority)–one that comes with a sense of excitement (not punishment). I want there to be a willingness to engage based on trust (not fear) and a willingness to persevere because of the promise of growth (not rewards).

Tis the season for classroom planning...

Rudi

My wife and I adopted a dog when we moved to Tennessee. We have wanted a dog for a while, but our apartment in Maine would not allow them.

Rudi is a three-year-old, German Shephard. He is pretty big--bigger than any other dog my family has owned. He is friendly and playful, and a bit attention-seeking. But if you ignore him for about five seconds, he will usually walk away and lie down. The previous owner had had him for those three years. He was house trained in simple ways, but beyond sit and one trick that was it, and he didn't really know sit.

After a day, we managed to get him to wait for our signal ("It's OK", and a tap to the shoulder) before moving through the doors leading into or out of our house. In about two minutes, we managed to teach him to stay inside any boundary we set for him (in the kitchen when we are eating in the dining room; in the hallway when we are in our bedroom, etc). In about two days, we also got him to be calm when we come home. Rudi was not leashed trained, but we got him to walk on a slack leash in mostly about 2 minutes in our backyard, and then another 5 min outside for a walk around the neighborhood.

Most of this was done by gently using our bodies. For defining boundaries, we simply 'backed' Rudi up with our bodies (no hands or arms), and calmly said, "Rudi, Back up". When he would cross the boundary, we would just do it again, until he got the picture. With the door, we would just crack the door open and if he made any movement we would close the door. We gradually opened the door more and more (occasionally asking him to back up), until he knew that the door would not be opened until he remained back. It took no time for him to learn that a friendly, "It's OK" and a tap means that you can cross the boundary or go through the door. For the leash, we just didn't let Rudi decide where he was going. If he pulled forward, we excitedly and happily turned and ran the other way and saying, "Rudi, this way." If he started pulling that way, we change direction again. There was no yelling or telling him not to pull, or yanking the leash in punishment. If he did walk with a lack leash, we would just continue forward. On the first walk, we had to turn around less than a half-a-dozen times. Since then, he has only pulled the leash a little as we are returning back to the house. Finally, Getting Rudi to be calm when we come home was also easy. When he came home, we simply did not say anything or look at him until he was calm, and then he would get our attention.

More recently, we have started to work on "Come" and "Stay". Stay has been easy, because it is part of the "back up". We are just using "stay" to mean, don't move at all, rather than "back up", which is move back and then don't move forward. With "come" we are using treats and praise to get him to come. I think next week, we will work on "Drop it". The only other verbal talk we use with him is "all done" with a crossing hands gesture, when we are all done playing with him or giving him pets. We then put toys away and ignore him until he settles. If he is still excited enough to come up and bother us, we simply pull our hands up, cross them, and turn away from him. He gets the picture really quick.

It is very enjoyable to train a dog without ever having to yell or feel angry. Using your body and a calm voice makes things so efficient, but also pleasurable. The only escalating sound we use is, "Bop bop!" with accompanying claps to get him to "leave something" alone -- like the trash can. But the sound is not used in anger. Rather, it's used in a distraction kind of way. It startles him and directs his attention to the noise and to us. Pretty soon we will work on a "leave it" command.

Anyway, I wanted to write about this because

(1) It's about learning and teaching, and

(2) I want to write another post about how I "learned" to be this way with dogs.

Help me think through a "physics praxis prep" course

If you were overseeing an independent study course where the explicit goal was to discuss and learn content that would typically be covered in the praxis exam for physics content knowledge, how would you structure the course? The course meets 2 hours per week and is targeted at physics majors who are in MTSU's physics teaching concentration

Obviously, we want students to be positioned to pass the exam, but I don't want to turn the course into a "test prep" course. Of course, these are physics majors who should know some physics pretty well, but as I see it, the exam covers a lot of content. Much of the content, students will likely have encountered before. Other content, they might have only gotten cursory experiences with or perhaps none at all. Even for content that's been covered, it doesn't mean they know it well.

If you are curious to know what's covered on the Praxis, here is some information on the multiple-choice exam and on the content essays

So where do we focus our efforts?... I think it's hard for me to make blind assumptions about what these students will need. So, I imagine a good way to decide how and where to start is based on a some assessment of their strengths and weaknesses. I could imagine asking students to rank their confidence in various topics, and then administer some assessment along those topics. We could then use their confidence rankings and the assessment as the start of a conversation for where we need to focus our learning efforts.

But what would I have students do? I think, too, that will depend on (1) how many topics areas students are going to need development in, and (2) how many students I have in the course.

Anyway, as I'm thinking this through, I'm curious to get ideas from anyone and everyone.

Reading Recommendation

I'm always amazed at the new meaning we find when we go back to reread something old a new. These past two days, I have been re-reading the following lecture series by David Hammer:

Hammer, D. (2004). The variability of student reasoning, lectures 1-3. In E. Redish & M.
Vicentini (Eds.), Proceedings of the Enrico Fermi Summer School, Course CLVI (pp.
279-340): Italian Physical Society.

Lecture 1: Case Studies of Children's Inquiries

Lecture: 2: Transitions

Lecture 3: Manifold Cognitive Resources

I highly recommend them.

Exposing Ignorance and Fostering Intrique

** 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

Poynting Vector in a Current Carrying Wire

Steve Kanim, who is a professor and physics education researcher at New Mexico State University, brought this cool puzzle to my attention a few years ago:

If you calculate the poynting vector for a current carrying resistor–considering the E field that drives the current and the B-field generated by the current, you get that the energy flux in the resistor is directed radially inward toward the center of the wire. If you don't believe this, figure out the direction of those fields, and use the right hand rule to calculate the cross product. At first glance, this seems kind of weird. You would think that the EM energy would be directed outward, because, well because a lightbulb is a resistor, and a light bulb emits light, and that light is electromagnetic waves, and that light is certainly traveling away from the light bulb. Of course, there is nothing deeply troubling here, but that doesn't mean it isn't worth thinking through.

I'm curious: How are you making sense of this seemingly odd result? Are there different ways that you might make sense of it?