Physics&Parsimony

About physics and teaching

Archive for September 2011

Seeing is (not) believing

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I’ve seen research cited that suggests demonstrations are not always effective because students often remember what they think they are going to see, rather than what they actually see. That is, prior conceptions can overwhelm actual observation. Thus, it is better to have students actually touch the apparatus, take the data and “see for themselves.” That’s what I do by using Modeling Instruction in Physics. But just taking the data isn’t enough, as was demonstrated today in my class.

My class had produced system schema and free body diagrams for a series of situations involving two carts in contact. These situations included constant and non-constant velocity, equal mass carts and unequal mass carts and even a collision between carts of unequal mass. While the students tried to puzzle out the FBD’s together, great questions about the relative magnitudes of the forces on the two carts come up. We then moved into the lab where the students were set up force sensors mounted on carts so they can try out each of the situations for which they’ve been drawing FBD’s. After data was taken, we went back to the classroom and each lab group whiteboarded one of the situations and explained what they found regarding the force that each cart exerts on the other cart.

The first group that reported on a non-constant velocity situation reported that the force that cart A exerted on cart B was, in fact, larger than the force that cart B exerted on cart A. The class sat silent while this sunk in. I asked if everyone’s observations coincided with this group’s observations. Total silence. After a bit of prodding to take a stand, they all admitted that they had measured the two forces to be equal. At that point, the group presenting admitted that their own data showed equal magnitude forces, but they just thought they should be unequal, and “kinda remembered” that they were unequal.

This led to a great discussion about our ability to fool ourselves, and how science can be thought of a set of behaviors designed to avoid fooling ourselves. The important point, I think, is that only by allowing students to present and defend their results (making mistakes and owning up to the mistakes in the process) does such an opportunity come up. Today’s class felt like a huge win, and I sincerely hope my other section of Honors Physics makes some kind of mistake just this good tomorrow.

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Written by Mark Hammond

2011/09/27 at 17:50

Posted in mindset

Junot Diaz on Accreditation vs. Education: Not getting *expletive* by mistakes

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Junot Diaz, the Pulitzer Prize winning author of The Brief Wondrous Life of Oscar Wao, spoke to our school community this past Friday night. He was a riveting speaker whose talk has already generated huge amounts of discussion within  the community (and not just because he’s the only speaker we’ve had who made no attempt to modulate his language in an effort to appear respectable).

During both of my classes with sophomores on Saturday morning, students made the observation that Diaz would like the way I teach physics, specifically because of my emphasis on making mistakes in order to learn. The subject of making mistakes came up while Diaz was talking about problems in our educational system. He made the distinction between accreditation and education. When the name of the school means everything, and the only goal is the next step of the process (getting into a big name high school, getting into a big name college, getting a job with a big name firm, making lots of money), then what is happening is accreditation, not education. So for our students, this means that getting a St. Andrew’s transcript with an appropriately high GPA could be viewed as the accreditation they need for the next step in their journey to… what?

Diaz differentiated accreditation and education several ways, but the difference that caught my students’ attention was that mistakes are fatal and debilitating during accreditation. “You make a mistake, and you’re f*****.” Diaz argued that mistakes are critical to learning, so if student are going to be educated, they need time and space to mess up, figure out how to fix it, and reflect on what they did. Mistakes are crucially important for education, but to avoided at all costs for accreditation.

Diaz admitted graduating high school without passing a single math or science class. When I hear stories like this, I think of all the times I’ve heard criticism of my standards-based grading system to the effect “There are no second chances in <fill in subject name>.” Diaz needed a second, third, fourth chance, but the system gave up on him too soon. When I see grades averaged across an entire semester, I wonder what is important–the average of where the student started and where she ended? Or is where the student ended up more important? For accreditation, the average of where the students started and where they finished is important, because the task is to rank students for the college selection process. Letting grades reflect only what the students know at the end of the course is education, because it helps the student to track what they learned and it reflects what they learned, not where they started. If college admission offices have a problem with this, I suggest they ask their professors how educated are the accredited students they admitted.

Written by Mark Hammond

2011/09/25 at 19:12

REAMDE: When does gamification work?

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While I’ve been too busy with the start of school to post anything on this blog, I somehow found time yesterday to start reading Neal Stephenson’s new novel, REAMDE. Once I got started, it was hard to put down (although I’m in no danger of finishing this beast anytime soon). About 12% of the way into the book Stephenson describes a marketing scheme pursued by an MMPORG that appears to be one generation beyond World of Warcraft. The marketing scheme involves letting users program their own apps within the game in order to do actual real world work disguised as medieval warfare (with all the goblins, dwarves and elves you would expect in such a game). The apps thus developed take the most stultifying, boring and mindless work (think TSA agent watching a single exit for eight hours, scanning widgets for imperfections as they roll past on an assembly line, or sitting in a business meeting) and turn them into a game. In some scenarios, the players in the game actually help the worker.

Stephenson makes the case that boring and mind-numbing tasks result in a rewiring of the brain so that fewer neurons (and less energy) are spent on the task. Neurons are reallocated away from areas of the brain responsible for repetitive, boring tasks (thus increasing the probability of mistakes when that occasional “interesting” thing happens) and toward areas that are being used more. Gamification of the boring task brings attention and energy back to the boring task by making it more complex and interesting. Thus fewer mistakes are made and productivity increases.

So this got me thinking. Why would I gamify learning in my classroom? Do I really think that physics (or math) is so simplistic, boring and repetitive that the areas of the brain responsible for doing these tasks is atrophying? No way. We don’t need no stinkin’ badges in my classroom. Gamification is not required, because the job itself is interesting, connected, deep and engaging.

Written by Mark Hammond

2011/09/25 at 08:59

Posted in Uncategorized