…But Modeling Instruction Works Better

In my last post, I suggested that one of the ways to approach the subject of curricular and pedagogical change with colleagues, especially as it pertains to modeling instruction, is to share one’s own personal story of transformation. So here’s mine.

I used to be an awesome teacher. Seriously, that’s what everyone used to tell me and I had started to believe them. For the first six years of my career, I did my very best to make my classes dynamic and engaging by incorporating various types of activities. During lecture, I was enthusiastic and worked hard to distill an idea down to its essence when explaining it. My reviews from students were always glowing and the administration loved what I was doing. And the awards! In those six years, I taught at a rural public school, was a TA at a state university and spent the final year of the first six at my current school. In that time, I won three teaching awards and was nominated for two others. By every measure I had available, I was a great teacher. And then, the FCI came along.

The FCI (or Force Concept Inventory) is 30-question, conceptual multiple choice test meant to determine how well the students in your class understand the Newtonian concept of forces and the results of their application. No calculations are involved. The FCI came to me through Dr. Kathy Harper at OSU. She had presented a short, one-day workshop on modeling instruction locally and had followed up with flyers inviting the participants to the summer workshop. I signed up and as part of the process, I was asked to give my students the FCI before coming to the workshop. Looking over the test, I thought my students would make short work of it. After all, we were ending the year on magnetic induction, so surely they understood Newton’s laws of motion. We’d been using them all year. With the first year at my new school ending, I administered the FCI to my students. When I reached the summer workshop, I eagerly sought out the results.

College Prep Physics – Mean = 6/30 (20%)

Honors Physics – Mean = 9/30 (30%)

AP Physics C:Mechanics – Mean = 13/30 (43%)

WTF?! How were those scores possible? I spent a year teaching those students physics. The FCI covers some of the most fundamental ideas I told them about. They got As and Bs! The AP scores were all 4s and 5s! While I didn’t expect perfect scores, I did expect results significantly better than guessing. Those FCI scores were like a swift, spiritual kick to the head that altered my reality forever. I had to figure out what was going on. I began by doing what every normal person would do in this case – I blamed the test.

When I started the workshop, my skepticism for modeling instruction was high – very high. Of course, kids taught with modeling do better on the FCI – it’s written by the people that developed modeling! How does it relate to other measures of physics learning? (It correlates very strongly.) How many students do we have data on? (At this point, n> 10,000.) Students still learn by lecture. Why bother changing? (Because more of your students will learn more material using modeling.) All of my questions had answers. The research on modeling instruction and the tools used to evaluate it is extensive. (Here’s a start.) As a science teacher, if I’m going to talk the talk, I need to walk the walk. Having been confronted with what I found to be convincing evidence, I was obligated to investigate this pedagogy and see if it had an effect on how well my students understood physics. After the workshop, I returned home, prepared for the coming year and did my best to implement modeling in the following months.

It was difficult. I felt like a first year teacher again. Rushing home to review and prepare for the coming day, I was forced to truly change the way students engaged with the material and forego much of what I had developed over the past six years. Too many times, I’d start to revert to simply explaining some idea rather than forcing the students to provide the explanation. As the year progressed, it became even more difficult as we started covering content that the workshop never got to. I’d never been good at writing assessments and my old ones weren’t addressing the things I was now asking about. It was a mess. But there was a noticeable shift in how my students were acting in class. They began to enjoy the content rather than the show I used to put on. Their confidence in their knowledge was much greater than it had been in the past. But, to my critical eye, those things, while very important, were not measures of how much physics they’d learned. Was this admittedly chaotic year more productive than the way things had been in the past? For that comparison, I needed the FCI.

At the end of that first year of modeling, I only gave it to my honors physics class. I hadn’t taught college prep that year and hadn’t used modeling in AP. Nervously, I scored the tests and tabulated the results:

Honors Physics – Mean = 18/30 (60%)

I stared at that result for a long time. Even in the face of the frankly terrible job I felt I had done that year, my students had shown incredible learning gains. The next two years showed even greater improvements on the FCI as I refined and adapted modeling instruction to my own style of teaching. The pre- and post- scores remained consistent with the national averages. Additionally, enrollment in the 2nd year AP Physics class has grown from 4 to 13. AP scores remained high. And the unmeasureable qualities I mentioned earlier continued to grow in both intensity and frequency. From those results, I had to conclude that modeling instruction was more effective than lectures at producing lasting learning and getting students to adopt a Newtonian view of the universe. That seems like the only logical conclusion to draw. It would be irresponsible of me to continue to teach the way I had been when confronted with this information. So, I started using modeling and have not gone back. That’s my story.

I’ll leave you with this analogy. Newton’s law of universal gravitation works. We used it to discover Neptune and Pluto, both invisible to the naked eye. It predicts the paths of comets and dates of eclipses. We could continue to use it, but then we’d miss out on solving the mystery of Mercury’s perihelion, the bending of starlight, GPS, black holes, the origin of the universe and more. If you know about general relativity, but refuse to use it, then all of those problems remain unsolved. I refuse to leave any tool unused that will demonstrably improve the knowledge and experience of my students.

Lecture Works…

Recently, the Twitterverse has been awash with debate on the merits of traditional lecture-based instruction in science classrooms. I’ve watched with growing concern as many of my progressive colleagues have made claims that “Lecture doesn’t work.” or that “Kids don’t learn from lecture”. These blanket statements are both demonstrably false and harmful to the dialogue and discourse about research-based practices that many of us support.

Let me be clear about this: lecture can be used to teach students. That’s not my opinion. That’s a research-based conclusion that can be drawn from this graph:

from How Effective is Modeling Instruction?

If you have trouble reading the graph, the vertical axis is the mean FCI scores for students in physics classes and the horizontal axis is the type of  instruction students received. See that first bar? Students in a traditional (i.e. lecture-based) class, showed a gain of 16 points from pre- to post-test. That looks like learning to me.

Now, you might be saying, “But what about the modeling bars? Even novice modelers achieve greater learning gains with their students than lecture-based classrooms.” And you’re right. However, when comparing those bars to the traditional one, all I can conclude is that modeling instruction is more effective than traditional instruction. Those results don’t invalidate the gains showed by the students in the traditional classrooms, nor do they invalidate the methods used in those classrooms. Teachers who use lecture have students that learn. (I won’t even go into the anecdotal evidence. Suffice to say, that I only received traditional instruction and I think I know a thing or two about physics.)

I love modeling instruction and I wish that every physics and chemistry teacher out there would undergo the training, adopt it and use it in their classrooms. Like many of my colleagues, part of the reason I join the conversations on Twitter and write here is to spread the word about this amazing research-based pedagogy. When I see teachers curious about it or challenging it, I like to talk to them and find out what they’re thinking. But, if I lead with a statement like “No one has ever learned by lecture.”, they’re going to think I’m foolish and give much less consideration to the rest of what I have to say. It shuts down the discussion before it can even begin.

Getting teachers to take a look at modeling and seriously consider it requires them to challenge their preconceptions about the way education works. Mine came with my first post-test FCI scores. Malcolm Wells, one of the fathers of modeling had a similar story. I think most of us come to appreciate and understand modeling instruction through redesigning the model of education that we have built in our heads and that we have implemented in our classrooms – not by being told that what we were doing was wrong. Ironically, lecturing people about it just isn’t that effective. Instead, if you find yourself with the opportunity to share your passion for this method of teaching offer the evidence that supports modeling or even better tell your own story about how you decided to change your viewpoint. Give your colleagues the chance to discover what you’ve known for a while now. I promise that if you let them do that, you’ll be more effective.

I Love Lab Practicums and So Should You

I love lab practicums. If you don’t use modeling instruction, the name may have a different meaning for you. In modeling, a lab practicum is a deployment activity in which students are asked to use the model they have developed to accomplish a specific task. Ideally, the arbiter of success in the task is Mother Nature. They might be graded, might not be, but they always provide students feedback on their understanding of the model being studied.

The classic example in modeling is the constant velocity buggy crash (aka the two-train problem) Having already determined the velocity of their own buggy while developing the constant velocity model, each group is paired with a second. They are challenged to use the constant velocity model to determine where the two buggies will collide if they are started at opposite ends of a horizontal ramp. They cannot run both carts together until they have made their prediction and are ready to test it. The excitement and enthusiasm students show for these activities is infectious and the assessment of their knowledge is raw and honest. They can’t hide from it. Either the cars collide where they predicted or they don’t.

As part of the #physicsmtg that I took part in, we brainstormed and shared alternate practicums that we could use for many of the modeling units. Here is a list of some of the ideas tossed around: Lab Practicum Ideas. This is only a quick list and some of the names may seem strange. If you’re curious about any of them that I don’t cover below, just leave a comment. We also looked at Practicums for Physics Teachers by Henry Ryan and John E. Barber.

Friday afternoon, we decided to setup and test two different practicums and a demo that many of us hadn’t seen. Here are some quick descriptions that should allow you to utilize these in your own classroom.

1. Two Ramp Race (for Constant Force Model)

Kelly O’Shea shared a practicum with us that she had originally learned about from Matt Greenwolfe.

Start with one ramp already set up at a 10° angle and the other at 5º. Tell the students that you will start the cart on the 10º ramp one meter from the bottom. They have to determine where to start the cart on the 5º ramp, so that the two cars reach the bottom at the same time. You might let them run each cart separately or require them to just use their models to make predictions, but the test of their knowledge comes at the moment they place both carts on the ramps and let them go.

I like this one for two reasons. First, it’s a natural continuation from the constant velocity (crashing buggies) and the constant acceleration (race down the ramp) practicums. Second, it’s clear cut and requires students to demonstrate understanding of the core principles of the constant force and constant acceleration models.

2. Simultaneous Collision (for Conservation of Momentum Model)

Mark Hammond set this one up, but I neglected to snap pics. In this practicum, two low-friction plunger carts are placed on a dynamics track centered between two bumpers. To minimize the mathematical difficulty and emphasize the physics concepts, choose a total distance between bumpers such that the total distance covered by the carts is a round number (e.g. 50 cm). That is the total distance between bumpers would be 50 cm plus the total length of both carts end to end. Deploy the plungers and the carts will strike the bumpers at the same time creating clearly audible simultaneous sounds.

At this point, provide masses that are equal to the mass of the cart, so that the students can double, triple, etc. the mass of either cart. Give them time to experiment with the setup and discover the pattern rather than directing this part of the process. Once they feel that they have determined a predictive pattern, test them one final time by making one of the carts have a mass of 1.5m. If they can’t accomplish this, send them back to the drawing board rather than moving them on to the final stage.

The challenge arises when you next provide the students with a rock and ask them to use the setup to determine its mass. They may use a balance to measure the mass of the carts, but not the mass of the rock. By drawing on the predictive model they have built, along with their knowledge of conservation of momentum, they should be able to determine the unknown mass.

I find momentum-related practicums to be difficult to make exciting without expensive ballistic pendula or car crashes. This one is easily affordable and challenges students to reverse the application of a model in the same way as the Matching the Beat pendulum practicum does. The scaffolding in it is well done and customizable to the class that you are teaching. If students need the practice, do each of the instances above. If your class is full of super-stars, drop all or nearly all of it. I think that I’d like more practicums that I do to have this scaffolding feature.

3. The Tin Foil Capacitor (for Electrostatics model)

Frank Noschese led us through his awesome tin foil capacitor demo and we discussed how to develop this into a practicum. Check out Frank’s post (linked above) for a video demo of the setup. This is a great demo that can be used to look at the distribution of charges on the surface of a conductor. Electrostatics is very light on practicums and I think that there is one lurking in here somewhere, particularly if you roll it up with an insulator sandwiched between the layers of the roll (thanks for the idea, Frank!). This could get at capacitance and how it depends on area. I need to think on this one more over the summer and try it myself.

When it comes to assessing with practicums, the teachers in the room had a wide variety of practices. For instance, Kelly and Mark use the Two Ramp Race as a test in their class. The setup is in one room and when the students are ready to try, they can enter and test their predictions. On the other side of the fence, I tend not to grade practicums and only provide verbal feedback about their process both during and after the activity. Of course, since adopting standards based grading, I’m thinking that these practicums would make ideal moments to score students on the relevant standards. It would provide one more data point for them to measure their progress.

So, modelers, what are your favorite lab practicums?

Edit: Due to my non-existent Latin skills.

Modeling Workshop Year 2

The second year modeling workshop has been over for three days now. I’m rested, catching up on yard work and getting ready for the next trip. So, did I learn anything useful? Was it worth it? Would I recommend it to others? Yes, yes and absolutely.

Did I learn anything useful? – I learned a lot during this workshop. First, the more focused on your field/passions/interests that your professional development is, the more useful and meaningful it will be to you. While I can appreciate the big, whole-school, day-long workshops, it’s difficult to address the concerns of a primary music teacher, middle school math teacher and upper school Spanish teacher all at the same time. If you can manage it, get your school to devote some of its PD dollars and meeting times to targeting specific groups (e.g. grade level, subject, tech).

More specifically on the modeling front, I learned how to unshackle myself from the Big Red Binder (aka the 1st year modeling curriculum from ASU). The first year sets participants up with a wide array of units of study, including labs, teacher notes and assessments. But after you’ve used modeling for a while, you want to go beyond that initial curriculum. My AP Physics C class hasn’t been where I wanted it to be, and part of the reason is because I didn’t know how to create my own modeling unit for the topics we were studying. The 2nd Year workshop helped me to understand the nature of the modeling cycle and the narrative flow that carries the class from development of the model to deployment in a variety of ways. Constructing our own unit, as well as being students for the five other groups in the workshop, showed me the many forms that modeling can take while still maintaining the same important structure.

Was it worth it? -  Hells yes! Spending three weeks working intensely with colleagues that care enough to give up three weeks of their own summer just to be better at their job is pretty rewarding. When is the last time you participated in a PD opportunity where everyone wanted to be there? And, when you made that nerdy physics pun, everyone got it and laughed? And to see what these people created and to get their feedback on your own work was an opportunity not to be missed. But rather than speak in generalities, let me show you what everyone did:

Rotation (My group)

Circuits

Forces (for 9th grade physical science)

Measurement (for 8th grade physical science)

Acids & Bases

Equilibrium

Or if you want them all, here’s a link to the entire collection.

Feel free to peruse the files, use what you want and modify what you can. Everyone was happy to share their work and some folks even included contact info in case future users had questions. (Update: I forgot to mention that these units have not been tested in a classroom yet, so please consider that when looking over them.)

While everything was great, I should be fair and discuss pitfalls in case someone reading this is thinking of attending the second year. The only bad part about the workshop is being away from home for three weeks. Okay, the unending stream of lunchmeat wasn’t the best either, but at least it was free. Since the workshop was held in central Ohio, it means that I had to stay in Columbus each week. Being away from your family and home that long can take its toll if you aren’t used to it. However, if you’re lucky enough to live close to a workshop then you’re only looking at a small commute. If you’ve done the first year though, you probably already know this.

Would I recommend it to others? – Anyone that has taken the first year workshop should absolutely take the second year. It will strengthen you as a modeler and give you an opportunity to get feedback on your work from other teachers who use modeling instruction. Make the time to attend.

If by chance, you just can’t get enough reading about modeling workshops, check out the running posts over at Salt the Oats from a 1st year participant. The level of detail in his posts is amazing.

Modeling Workshop – Day Awesome

As I mentioned yesterday, these past two days were an opportunity to pilot a portion of our units with the rest of the advanced workshop participants acting as students. Today was our day to present and we tested our practicum for the balanced torque model. If you’ve ever taught rotational motion, I’m sure you’re familiar with it.

This problem is in every physics textbook, so we decided to drag it kicking and screaming into the real world. Here is our take.

Starting with only the board, first, without showing the readings, ask students how the readings on the two scales will compare. (We used force plates and Logger Pro.) They guess that they’re equal. Awesome. Show them the readings. Ask them what the readings can tell them. They figure the weight of the board. Cool, then hide the readings and push scale #2 in towards the center of mass, maybe 1/3 of the way in. Then ask them to use the balanced torque model to predict what the two scales will read now. Let them work through it and bring you their prediction. Check against reality. Horray!

Now, we ramp up the challenge. Since every physicist loves symmetry, we want to keep the scales at their new locations, but get them to read the same thing again. So, we drug out a crate of books. The challenge was to decide where to place the crate of books on the board so that the scales read the same thing. Make what ever measurements you need to, feel free to move the board, but you have to place the crate on the board yourselves.

To say that the teachers in that room were engaged was an understatement. Not all of them had the background for this topic, some of them had it in the past but had forgotten it and some were well versed. We were lucky to have so many hard-working “students” in our class. Tyler and I circulated around the room, helping where needed, being less helpful when we could and looking for misconceptions that our students may have. Overall, awesome presentation. But in all honesty, I don’t care about how well it went for our sake, because here is what I want to share tonight. Here is the power of modeling instruction made manifest.

One of the teachers today came into the unit having studied rotation years ago in an intro physics class. Her knowledge of this topic had been long forgotten when we unveiled this problem today. I spent some time at her table, talking to her about the ties between balanced force and balanced torque. It was clear, she wanted to learn. Why? Her grade for the workshop (we can earn graduate credit) didn’t depend on this activity and all she had to do was provide us with anonymous feedback on which she could have written very little or even a message about how this was beyond her experience. In other words, she had no vested interest in this problem and could have easily given up. But she didn’t. She dug in, wrestled with the ideas, tried things, failed at them, and tried some other things. She dealt with her confusion and frustration head-on and then, just as we were wrapping up, brought me an answer and excitedly asked if it was right. We uncovered the scale readings and she was spot on. And then, this adult woman, who had just spent 30 minutes working to learn something for no other reason than to know it, burst into dance. The joy she felt at having learned simply could not be contained. I wish her students could have seen her today.

Dammit! Do you people get this?! If this was a problem in the book for homework, do you think she’d have that reaction? She said later that she probably would have given up frustrated if it were. I bet your students do that and then come in the next day and ask you to go over the homework. Anyone reading this probably does get it since you’re interested in modeling instruction. But to you then, I have to ask, how do we get more people to see the power of this? How do we get them to realize that we can make our classrooms – any classroom – about learning and not about grades?

Modeling Workshop – Day Eight

The rubber met the road today for four of our groups. This was the first opportunity for groups to try out material they had developed on the rest of us (in student mode) and solicit feedback about it. It was an incredibly insightful day for me and our group didn’t even get to present yet!

The groups that presented today included an underpinnings unit that ran us through a measurement activity, a physics group who had us develop Ohm’s Law and two chemistry groups. Now, I’m unfamiliar with chemistry modeling but I was immediately struck by the notion that we were no longer dealing with things but instead with the idea of things. There were no hydroxide ions in front of us, only a blue liquid, a clear liquid and a sensor that gave us some number. And when learning about reversible reaction rates and equilibrium, the activity actually required us to represent concentration of reactants and products with volume of water in straws. Both activities were well constructed and interesting to me, but the level of abstraction required as a student was significant. According to the teachers, not every activity is as abstract as those today, but when you’re driving principle is that the entire material world is made up of tiny particles, you can’t really avoid it. As a chemistry teacher, it falls on you to construct opportunities for the students to develop this model, and if that fails, you need some means of convincing them. The only reason they have considered this particle model as a possibile explanation of reality is because you suggested it. Contrast this with physics, where students already have a pretty developed set of models to explain the world based on their own observations.

As a physics teacher, I want to bring more of modern physics into my classroom but to do that I have to confront the same challenges that my chemistry colleagues do. How does one tease Placnk’s constant from the light of LEDs? Or the idea of dark matter from galaxy rotation curves? Are high school students cognitively capable of making these connections? I think back to how excited these ideas made me when I discovered them in high school (Yes, I was a geek even then.) and I want to share that excitement with my students. No one thinks physics is cool because of boxes on inclines. It’s cool because it predicts weird things beyond our imagining and then proclaims that they are real. No other high school class can do that. I don’t know how to bridge this gap yet, but I need to figure out how.

Modeling Workshop – Day Seven

The second week of the advanced modeling workshop is moving along at a good clip. The primary activity that dominates our days is the development of materials (assessments, practica, labs, etc.) for our unit. The pace can feel intense at times though it has not overwhelmed us yet. A few key pieces of what we have accomplished include:

• a final storyline that details what models we are developing, how we are deploying them and how each activity serves the models
• a working rotational inertia apparatus (prototype)
• a fun practicum involving a balance beam, two bathroom scales and an additional weight

Much of my evenings are spent reading articles, writing more material and completing the small reflective assignments we are given. Tomorrow begins the process of testing some of the materials with other groups. I’m looking forward to getting some feedback and the chance to see what some other groups have developed. 

Today’s discussion developed out of an article by Eugenia Etkina regarding weekly reports as a means of determining student understanding and allowing students to reflect on what they have learned in the past week. The three questions students are asked to address in the weekly report are (1) What did you learn this week?, (2) What questions do you stil have?, and (3) If you were the teacher, what questions would you ask this coming week to make sure students understand the material? I’ve wanted to begin including some reflective writing in my courses for the past few years, but I hadn’t found the right prompts nor the right delivery system. Dr. Etkina has come up with these great prompts that allow for some really amazing insight into what students think they know and what I might be doing a poor job teaching them. However, in the article we read, she had only 17 students, so managing this much reading and providing meaningful feedback was manageable. I’m really lucky in that I typically have between 50 and 60 students in a year, but even that would quickly become overwhelming and I know I would let these slip to the bottom of my to-do list, especially if they are hand written.

Our group had asked during the discussion about electronic submission and then I recalled this awesome post by Chris Ludwig – Blogging in the Science Classroom: The Worksheet is Dead . I think student blogs would be a fantastic way to implement this and Chris’s idea of using Google Reader to manage them is brilliant. Not only could I provide feedback directly to the student, but other students could comment as well and even set up their own readers if they wanted to. Seeing that they each had questions would also make it easier for them to ask questions during class and alleviate the ever-present attitude of “If I don’t get it the first time, I’m stupid.” thought process. I’ll most likely pilot this in my AP class next year as they are used to my crazy new ideas.

Modeling Workshop – Day Four

I don’t have a lot to write about today. The entire morning was spent working on our unit. We’re making good progress and have compiled a list of learning objectives (aka standards), matched them to the AP standards since Ohio doesn’t seem to care if your kids know why things rotate, and knocked out two assessments. Today’s article discussion continued the theme of alternative problems/assessments with the focus on ranking tasks. I like these a lot and we’ve incorporated a ranking task activity into our unit involving bars like these. I’m going to build cheaper ones though. There was a good discussion around the placement of the explanation portion of ranking tasks from a suggestion that students be prompted before the ranking portion of the exercise to engage them with the idea first.

Eventually, we have to come up with two alternate problems to present and include in our unit, so I think the other one is going to be a goal-less problem. I’ve wanted to try these since I first read about them on here and here. They appear to have originated from Paul D’Alessandris (ref), but I can’t find much literature on them. In particular, I like that as students develop a wider array of knowledge, you can revisit older problems and see what additional layers they add to them.

Tomorrow is a short day and then I’m driving back home for the weekend, so I’m not sure if I’ll be posting. I do have some thoughts on the whole Khan Academy firestorm and I’d still like to tell my pseudoteaching story, so maybe I’ll try tackling one of those this weekend. Thanks to everyone for reading this week!

 

Modeling Workshop – Day Three

Work continues apace on our unit. Our desire to develop no less than five models (balanced torques, constant torque, rotational inertia, angular momentum and rolling motion) has had to face reality and deal with the fact that the workshop is only another 11 days long. I believe we will restrict ourselves to fully developing the curriculum for the first three models above, but attempt to include as many notes as possible for the other models.

While much of the day is devoted to working in our small group and fielding questions from the workshop leaders, we did come together as a class for two discussions. First we tackled the questions of “What is modeling?” and “What makes modeling modeling?”. That first one is a tough one to answer. I’ve always relied on simply describing the initial pendulum unit to convey the difference in how the class is managed and constructed. As other teachers mentioned today, you still get responses like “Oh, I do a lot of labs/demos in my class too.” or “Oh, that’s inquiry learning.” which both miss key components of what the modeling cycle entails. One of the best responses today was that modeling is a way to organize your curriculum. Everything you do, from development to deployment, including assessments, is directed toward explaining, refining, testing and breaking the model and so, the model must be the core component of the curriculum.  This means that if you want to develop a new modeling unit, the first question you have to answer is “What is the model I want my students to build?” repeatedly followed by “How does this question/activity/lab address the model?”.

The other discussion was about our article reading. Two articles were assigned this time – one on the role of the lab practicum and the other on context rich problems. Now, I love lab practica and try to include one in every unit we study. I think they are a fantastic means of assessment (though I don’t grade them) and they push students to really develop confidence in their initial model development. Context rich problems though rub me the wrong way. They seem filled with unnecessary and unrealistic context, at least from my limited exposure to them. Here’s an example:

Roller Splash: A company that designs amusement park equipment asks you to design a new roller coaster splash ride. A cart with passengers starts at rest and rolls down an inclined track to a horizontal section at the bottom where it flies off to land in a pool of water – what fun! For more excitement, physics students using the ride must decide their starting position in order to land safely in the water. You are asked to build and test a miniature model. For this model, determine the position of the Hot Wheels track that a Hot Wheels car should start so that when released it moves down the track and flies off the horizontal section to hit the target on the floor.

So much of this bugs me. First, all of these seem to be couched in terms of “you work for a company…build a miniature model”. Unfortunately, your miniature model is nothing like the real ride. It doesn’t account for weight distribution of people (How many people are on the ride and does their weight matter?), drag forces, rolling motion, how you would get this rolling car out of the water and more. By dressing it up this way, the author seems to be indicating that this topic isn’t interesting to students normally, so we’re going to try and make it interesting with some flavor text. You don’t need to describe a “bungee jump system that provides the jumper the extra thrill of just missing the ground” (because no company would ever actually build this!), just hand the students a spring and an egg and say “Okay, you’ve all learned about energy and springs…decide how high to hang your spring so that when I give you a 200 gram mass to attach at the end and drop, it doesn’t crack the egg lying directly underneath it.” They will work so hard to protect that egg and the excitement in the room will be palpable when that first student lets go of the mass.

Now, I’ve heard good things about context-rich problems elsewhere and I like the actual activities as they are really just lab practica. So, what am I missing? Why is that silly context so important? Or isn’t it?

Modeling Workshop – Day Two

Okay, time for a confession…I’m a thief. Like many teachers, I hunt through old texts, dig through others curriculum, chose what I want, modify it, discard the rest and pass it off as my own assessments. It’s kind of odd when you think of how much we harp on plagiarism, but we “borrow” liberally from other teachers ourselves. All of this is just my round about way of saying this – I do not have a lot of experience in designing curriculum. Turns out, it’s a lot of hard work.

Today started with us jumping right back into working on developing our initial storyline for our model. We needed to decide what model(s) we were asking the students to develop, identify what representational tools would be needed, the investigations they would use to develop these models and the general sequence of events. Thankfully, this is our first draft, so we can get it wrong. We’ve identified our model as the rigid rotating body model and have kept the general flow of torque -> rotational inertia – > angular momentum for now. I won’t explain everything right now as I’d like to share the work with the interwebs when we’re finished, but here are some pics of the madness that emerged from our minds:

My partner, Tyler, snagged the torque simulation from PhET and we think we can put it to good use in building the model of torque. Our main tactic is to let the students build on previous knowledge to draw conclusions, so we lead off by repeating the hover-disk questions from the BFPM but now applied to a rotating disk. I’ll let you have fun trying to chart our course through the whiteboards in the photos. Suffice to say, we are very happy with how we lead the students through a development of the idea of balanced toque on a rigid body, constant torque and the rotational inertia of a rigid body, but then we stalled at angular momentum (Check out the far left board in the pic above.)

This might have been my fault, but I just wouldn’t settle for the standard demos. I want a phenomena that not only requires angular momentum to investigate, but also one that will invoke questions from students, not physics teachers. And I want to avoid that feeling of contrivance. It should feel natural. We wracked our brains trying to come up with something beyond the spinning ice-skater and flipping the bicycle wheel. I’m not saying these aren’t great demos that are cool to see, I just think few kids would be interested in them if their physics teacher weren’t drawing attention to them. We talked to everyone at the workshop about our mental block too, and people were supportive and offered ideas. It’s great to work with folks who will put aside their own work to help you make yours better. There are a lot of good folks at this workshop.

After lunch, we spent time discussing this article by David Hestenes. We do have readings from journal articles each night and we spend time the following day discussing them as a group. The article sparked some good discussion points, but I think we all still feel kind of new to each other so the conversation felt a bit stilted at times. If you’re a modeler and haven’t read this, I highly recommend it. If you aren’t a modeler, it is worth a look, but I don’t think some of the explanations will resonante with you as much as they do with me.

We wrapped up today by presenting our first draft to the entire group. This was a great way to organize our thoughts into something more coherent than the atrocity you saw above. Additionally, we could field questions and ask for assistance on particular trouble spots. Some of the other advanced groups are working on the following units: forces for 9th grade physical science, circuits, chemical equilibrium, acids and bases, and scientific underpinnings. It’s a very nice mix.

Finally, I wanted to mention how awesome Twitter is for professional development. If you read the Day One post and saw the challenges pic, you noticed that one of the issues mentioned was feeling alone as a modeling teacher in your building. Many of us who are new to modeling are the only ones in our building who are using it. Well, be alone no longer! When Tyler and I found ourselves stuck today on angular momentum, I put out the following tweet:

Avengers Assemble! It was like this awesome call to a super-hero team. Over the course of the afternoon and evening, tweet after tweet arrived bearing examples of angular momentum. Other teachers shared eight different ideas including the following awesome video (Merry-go-round video). Oh, and literally as I’m writing this another popped up on my Twitter feed. So awesome. Seriously, if you are a teacher, get on Twitter.