Day 3: Summer Work and Explaining the CVPM Model

What does summer work look like for AP Physics 1? I don't want them to start doing any physics, because they don't know how the class works yet. But summer work is a good way, I think, to have students check in with their math skills and see if they know some of the mathematical moves they'll use in the class. I've posted two pages from the seven pages of the summer work above. The other pages are about simple trigonometry and literal equations.

We whiteboarded this problems today. I was happy to see that classes were ready to ask each other questions, without putting all the questions through me.

After that, it was time to sketch out, quickly, CVPM (the Constant Velocity Particle Model). Many units in this class are about the four representations we use to describe them:

• Diagrams: I introduce the motion map by doing an example. Sometimes I'll talk about a car with a leaky fluid. Other times, I refer back to what students did in lab to measure the speed of the buggy. I don't spend too much time on it. I focus on doing one quick motion map, asking if students can tell where are walked faster/slower/stopped, when I was walking forward/backwards, and move on.
• Algebra: Another quick one. At this point, I don't want to show all the equations we could use. Some students, as soon as they see an equation, use that representation above all others. I understand why; they take years of classes in the math wing where the equation is the best representation. So I try to deemphasize it as much as possible. I ask students what equation they used in math class to solve questions about speed. Here, I usually hear s = d/t; at other schools, I've heard D = RT. I write down either. I ignore it for now. (Later, when we've developed a good equation for velocity, I'll add it to the notes here, but not yet. I'm just keeping this representation open as a possibility.)
• Words: What words will we use for to describe this motion. Starting point, velocity, fast/slow usually come up quickly. I often have to give an example until forward/backward comes out. I don't like forward/backward because in this model, points don't have a front. I will sometimes do an example where I walk both forwards and backwards from the left side to the right side of the room. My belly button does the same motion, even though one is forward and one is backward. So I tell them, since I'm mathematical, I prefer positive direction/negative direction.
• Graphs: We found from doing the buggy lab that graphs are a great way to show your results. So a straight line on the position-time graph means constant velocity. We then answer these two questions: What does the vertical intercept mean in this graph? What does the slope mean in this graph? They are very useful, and that fact allows me to reiterate how important graphs are to physicists.

I don't always teach these four representations in this order, but I wrote them in this order because it's how I remember to do all four. I use the acronym DAWG. It's very 1990s, but it works for me.