Category Archives: Uncategorized

The Seeds of Climate Change Denial (or Newton’s 3rd Law)

Today in class we were working on practice 3 from my Momentum Transfer Model (MTM) packet (which is a combination of standard modeling questions, Kelly’s questions, and a couple I wrote maybe). In first period we did problems 2 and 3, below, in a row. After problem 3 I gave students one of my standard speeches about how some students decide physics is about choosing an answer and then switching it because they know they’ll be wrong. I try to emphasize a number of times throughout the course that a good scientist isn’t one who’s initial intuition is correct; she is one who is willing to take a step back, consider the science of the situation, and then make sense of it. Anyway, in 1st period, almost every student choose that the VW experienced a greater force in 3a, despite the fact that we did quite a bit of work with Newton’s 3rd law, work I still think is pretty effective, back in November. The problem is, students haven’t made it second nature yet to start with science and end with conclusions. They start with their gut and go from there.

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During 2nd hour I inadvertently gave my speech between questions 2 and 3. Every kid said that the forces were equal in 3a. Every kid.

This helped me to realize that even when students understand a concept at some point, they still tend to revert back to gut-first thinking over time. In this case, the students were attempting to make sense of the situation, but without considering the physics involved they tend to confuse acceleration (the affect of the collision) with the force of the collision itself. Instead, if they start by applying Newton’s 3rd law, such that the forces are equal, then apply Newton’s 2nd to show that the effect of that same force depends on the mass of the object, it makes sense that the forces are equal but that the effect, the acceleration, is different.

So it’s not really that big a deal in the scheme of things when students’ don’t correctly analyze a collision, but it’s a much bigger deal when we have policymakers denying climate change. The problem is summed up in a picture from a tweet that came across my feed the other day;


Teaching science should mean giving students the tools to analyze situations and make logical conclusions while at the same time emphasizing how to do so in a variety of situations. If we fail to give students the tools of science, or show them how they apply, or challenge them with different situations, or reiterate their prior understandings, we leave room for them to revert to gut-oriented thinking. I hope that my preaching about starting with science rather than intuition can help in some small way to move our society from one where people try to ‘prove’ their own biases to one where we use data on a real quest for truth.

Don’t Keep it Simple, Stupid

Teaching is hard.

I don’t mean that there’s a ton of work that can never get fully done (even though there is) or that parents/admin/the general public are hard to deal with (even though they are). I mean that crafting a quality lesson, set of lessons, unit, or entire course is really, really hard.

Every once in a while I run into a former student from long ago who tells me how much they enjoyed my class, and all I can think about was how horrible a teacher I was then compared to now. But I wasn’t a horrible teacher; I just wasn’t as good at it as I have become. I can only hope this will continue to be true 10, 20, 30 years into the future.

Over 10 years of teaching I’ve learned a lot of skills to incorporate into my teaching. I started out teaching Physics and Geometry via overhead projectors (you know, the kind with wet erase markers?), because if I was going to give scripted notes it seemed like a waste of time to write them on the board each hour (turns out scripted notes in general were the waste of time). Over the course of the first 5 years I learned a lot about teaching through inquiry in my physics classes; I went from stating emphatically in a grad class that it was too difficult to guide students through inquiry to being a leader in my 6-12 department on the subject. But that took a solid 5 years and lots of failure; I honestly only succeeded because of lots of support from a mentor through my grad program. Good inquiry learning requires a very structured release of responsibility to the students and a general culture of inquiry throughout the entire course. It took all of 5 years to work out all the aspects of this to implement successfully.

Then I started incorporating a home spun, mediocre version of problem based learning in my geometry classes, though at least it upped engagement and increased learning based on final assessment scores. That took a solid 3 years, and in reality required my inquiry background to accomplish. I only stopped because by this point my physics classes had grown to the point where I became full time in physics and had to drop teaching geometry; honestly, I still had a long way to go and hope to incorporate what I know now about ProbBL back into math classes at some point.

About this time I discovered Modeling Instruction, which taught me, among other things,  how student dialogue can significantly increase the depth of student understanding. I’m three years in and have a long way to go before I’ll consider myself an expert.

So here’s the rub; I’m 10 years in and I know I still have a ton to learn. I’m not that great at facilitating student dialogue yet. I have a long way to go in helping students solve real problems in math class. I struggle with helping students who give up when challenged. I’m sure there’s many other aspects of teaching out there I have yet to learn.

For this reason I think we cheapen teaching by trying to simplify it. Silver bullets in many forms are always popping up in the education world, but quality teaching requires a blend of many talents, and it shows up in many different forms. I think this is why teachers get upset at things like administrators forcing the posting of objectives; emphasizing that over all other important aspects of good lesson design says ‘here, you’d be getting better results if all you did was this.’ It’s patronizing. I think this is also why I’ve never been satisfied with the SAMR model for integrating technology. ‘Oh, you’re only on augmentation? Your students will really be learning when you get to redefinition!’ There are so many ways to go analogue for quality lessons or to use tons of tech for shitty ones. Good teaching is far too complex to be boiled down into an acronym.

The false notion that creating a quality lesson is simple is also why we haven’t had successful education reform.We have a culture in the US built on instant gratification; no one is willing to wait the 15-20 years it would take to make progress. And no one is willing to take on the really hard work of making sure all teachers are trained and continuously supported in the many techniques that have been shown through research and practice to work to improve student learning. Instead we throw technology into the room and ask teachers to redefine education on their own using their 45 minute prep period, because we can do that in the span of a couple of years.

I hear teachers complain that their pre-service training didn’t prepare them for teaching. The problem is, it can’t. One can’t be fully prepared to find the right potion of techniques for a classroom without experience, trial, and error. Maybe this means that longer apprenticeship-like experiences with more built in support for new teachers would be helpful. I don’t know. I do know that there’s always room for improvement, and creating a national culture to actually support and encourage that would be a great first step.

This post was inspired by this tweet by Ilana and the conversation that followed.

Modeling the Mistake Game

I’ve been convinced for some time about the value of playing the mistake game, but I have been unable to get my students to successfully buy into it. Today we started graph stacks, where one of the three kinematic graphs (position vs. time, velocity vs. time, and acceleration vs. time) are given to students and they need to qualitatively sketch the other two. I wanted to use it as an opportunity to once again try the game.

First period I allowed students to work for a while on attempted the graphs, and then I assigned two groups the same problem. I asked one of the two groups to purposefully make a mistake and didn’t say anything to the other group.

2014-09-26 08.45.29While I liked the comparison, we ended up with 6 people in front of the room while all the conversation was focused on the three with the mistake. They rode it out and did a great job, but I still didn’t feel like kids knew what questions they should ask to back the group into a logical corner. So I decided to change it up 2nd period.

I again let students work for a while, and then I picked a problem and put it on the board with some mistakes embedded. The position vs. time graph is the original that was given, and the black on the v vs. t and a vs. t graphs is what I originally drew . The orange is the corrections we eventually made through questioning.

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I told students that I was going to model a presentation where we play the mistake game. I then gave the presentation; “The position is decreasing and positive so the velocity was positive but decreasing as well.” Then I gave them a minute to talk to their partners about good questions to ask.

And they didn’t ask good questions.

But what happened was that I was able to stop the minute someone asked a great question. “What is the slope of the position graph at time zero?” We then had a conversation about how forcing someone into a logical corner doesn’t happen with one question; it happens with a series of questions. So once I know that the slope of the position graph is zero at time zero, that leads to the logical connection that the velocity has to be zero at time zero.

Still, I didn’t feel like it went that well. So I let them work for a while again, then I picked the next problem and modeled it again.

They forced me into a corner in less than 2 minutes.

They learned through the first modeling session that a good question is one about the specific of the graph, not about what the person was thinking. Starting a question with “Why did you….” often doesn’t help. Starting instead with “What is the slope…” or “Are the velocities positive, negative, or zero…” does.

3rd period I repeated the process of modeling the mistake game with exactly the same results; it was painful the first time, and quick the second. I think I’ve got a keeper. Tons of students asked questions; they really seemed to be into it. Monday we’ll be trying the game with students presenting and I’ll update this post with the results.

UPDATE: Anecdotally, I felt like the day students presented their graph stacks with purposeful mistakes was one of the best whiteboarding experiences I’ve had so far. For each and every problem students were explicitly evaluating and analyzing every aspect of each graph, as opposed to correct graphs where they seem to say ‘yep, looks right.’ The quiz results were impressive. Out of a 4 point scale, last year the average was 2.36 whereas this year’s was 3.21 (p<0.0001). I’m in for the mistake game as a regular part of class from now on!