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?