Nicholas+Park


 * Monday, 7/26:**

Some very thoughtful reflections today.

I have also found that Arons' warning about presenting all those graphs in "one remedial orgy" is a sobering reminder of the importance of spreading things out over time. This chapter in general is very meaningful to me, as these issues come up again and again and underly many of the student difficulties that we see.

__//Where do we get these naive misconceptions from?//__

From the way our brains work. While this is not a course in brain science, it is approximately correct to say that our modes of thought are based on patterns of neurons firing that are directly influenced by our sensory experience and our thoughts about those experiences. And so life and memory is a process of building (private, mental) models. Two things happen here:

(1) We develop models that are the simplest representations of our experiences. For example, "motion cannot be maintained in the absence of a force" -- after all, we've never experiences a frictionless environment. So as teachers, we provide experiences to broaden our students experience and force them to confront the consequences.

(2) We develop isolated mini-models which we apply in different concepts but which are mutually exclusive - again, because this comes most naturally in the course of development. (Scientists do this too -- General Relativity and Quantum Mechanics come to mind -- but we know that we're doing it and don't want to.) So as teachers, we help them to confront these inconsistencies and develop a single model that encompasses all the situations.

(3) Our models and concepts are not completely formulated or clearly defined (this takes effort!). For example, velocity, speed, force, power, and energy all mean the EXACT same thing to many people, since they are not clearly defined. And so people think heavier things fall faster because they are not being sufficiently careful about the difference between the words "force" and "speed." We'll hit this one head on later this week.

//__What to do on the first day__//

So true that the first day is the same in every class -- setting expectations, etc. And what better way to set the expectation that this class is different -- that students will be actively engaged with each other and with the behavior of physical systems -- then to engage them with the material through lab and discussion on the very first day, and send them home with an assignment like the three questions I introduced. There is time to come back to classroom expectations, syllabi and such things the second day when the excitement has died down a bit.

The less comfortable students are with this sort of interaction, the more critical some sort of first-day activity such as the spaghetti lab, the bouncing ball lab, or the "wingspan" activity (graph students wingspan vs. height) can be. Dwain Desbian, an extremely successful modeler who has an entire community college curriculum to get through, spends a full week before introducing any physics. He feels that this helps get the students used to discussing and opining in a less threatening context, and it saves at least a week later on.

Other activities that can be done include a "following directions" activity in which students write directions for making a paper airplane, and then these are given to another group to follow "without making any assumptions" -- and then there is a race. In the post-activity discussion, the importance of clarity in communication comes out, leading students to see why we insist on clear definitions of any terms used.


 * Tuesday, 7/27**

Some reflection questions to consider: (1) What does an effective discussion look, sound, and feel like? (2) What sort of questions are most helpful in guiding a student to see the holes, ambiguities, or leaps in their thinking and to see a road to a clearly justified answer? (3) Of what does a solid justification for a step in a problem solution or a claim in conclusion consist?


 * Wednesday, 7/28**

Maikel's blog today presents a carefully reasoned perspective on the discussion question I opened with this morning. His position accords well with the ideas we're presenting to you. While many tools are useful in a proper context (we'll see this in our intro to force tomorrow, which I do differently every time I do it, drawing on a wealth of little demonstrations), they need to be employed in the context of a solid understanding of how people learn and specific aspects of the storyline and conceptual development in a given curriculum (which we'll also see tomorrow).

I also appreciate his point that "experience... is necessary to the making of a modeler." This is actually true of any domain of expertise: it takes an average of 10 years of **reflective practice** to attain expertise in any new field. This goes for teaching, physics teaching, and new methods of physics teaching. I've learned alot both during my 6 weeks of modeling training and in the 9 years since, and I learn more every year. In fact, I've learned several subtleties to shape the way I present some of these things through our interactions this week.

Lorien asks about instantaneous velocity. The best place to bring that in is during the first whiteboard discussion of today's lab, when we're looking at x-t graphs and figuring out how to handle the velocity trend. I often choose not to because I don't see it being successful and see it just clouding all the other issues I'm trying to accomplish. Let's discuss this today. At one point in the discussion, I pointed out how average velocities over smaller time increments might have been "better" in some way... with 5-10 more minutes of discussion, we could have teased out instantaneous velocity. We can go through this today if you like.


 * Friday, 7/30**

One term I am uncomfortable with both in the literature and in informal conversation is the phrase "traditional instruction," used in a pejorative sense. I'm much more comfortable saying "transmissionist," "presentation-driven," "teacher-centered," or something else that says what I really mean. Whether these are "traditional" depends on the background; one of the oldest teaching models is that of the apprentice, which is very "student-driven," and Socratic dialogue hails back as far as Socrates at least. In addition, not all lectures are bad. A full-class, teacher-led interactive lecture, with or without demonstrations, can be highly effective in the right context. The key is that (to name a few of the more important things -- not an exhaustive list) the content is organized in a coherent way that students are able to grasp and apply, that students are engaged with the content, that they have the background experience to understand the import of the conversation taking place, and that they are involved in shaping that conversation by expressing their own developing viewpoints. It is just that much of the time the types of activities that we are modeling are the best way to accomplish this.