Meet Me In The Back of the Room; Bring Nothing

I have been using this sheet to teach students how to draw the principal rays for concave and convex mirrors forever, as in before my current students were born. I think it might be time to redraw it; I no longer have the original. But it works so well! I feel, in my bones, the old, old mimeographs that I got when I went to high school in the 1980s. I really like it. I know it. I know its strengths and its weaknesses. I remember making it on my old Mac laptop. And the students are able to draw the diagrams after we use it. So maybe I shouldn't change it? 

Today we finished the curved mirror lab. We looked at the ratio of si/so and hi/ho. We also graphed 1/si and 1/so. We now have a few equations, but we're not sure why they work or how we can use them. We ended the day playing with the mirrors, seeing how the images change size as we bring mirrors closer and closer to our faces.

Today, we started by going over reflections in plane mirrors, and saw how Mr. Eye-Foot can help us figure out how big a mirror we need. Then we collected data on the images we could form from our LED F's. We will analyze the data in class on Monday. I didn't think we'd get this far, but I forgot how quickly I can go in these two small AP Physics 2 classes.

You'll notice I'm only talking about my AP Physics 2 class. I think it makes a good focus for the blog, and I want to use this blog to remind myself of what I'm doing each day and how it went. Today, I also did the following things:

• Went through a big stack of purchase orders to send them off to administration
• Fix a mistake in one of the purchase orders
• Help a colleague with a science class that seems over the safe number of students
• Taught two physics first classes, where we did my favorite lesson of lighting a light bulb with just one wire and one battery
• Graded binders from my physics first classes
• Helped a student who didn't finish his binder fix it when I stayed late to grade those binders
• Figured out how to fix Monday's lesson on the continuous conducting path in physics first
• Tutored two students in math in my study hall
• Tutored one student this morning in AP Physics C
• Taught my large AP Physics C class, where we did our first AP free response questions

And today was an easy day. Teaching is hard, y'all.

To give students an idea about sensemaking in physics, I took a page from Kathy Harper and used pinochle as a way for students to experience what it's like to try to understand the rules of a game when you only see examples of the game being played. After talking about "confusion is the sweat of learning" and how we use evidence to argue our points, I passed out just the first meld from this document to groups and watch them try to figure out the rules. I give hints about how the players only put down cards that will score them points and tell them what a trump is (many don't know!), then pass out the second meld, and then, after a few minutes, the third meld. It's always interesting to see who works with who and whether groups join forces. (I tell them afterwards I want groups to fuse if the going gets tough; we're smarter together than apart.) We then talk through the rules, and once a little has been figured out, it gets easier and easier.

I also told them to evaluate themselves on what they understand now, not on how they felt at the beginning of the activity.

We then debriefed on the reflection activity and started some practice on drawing reflections on plane mirrors.

We did our first whiteboarding today, which was really more about getting used to presenting your ideas rather than getting deeper with our understanding. I then talked about the two types of reflection; there's reflection off a rough surface, where the light goes in all directions, and reflection off a smooth surface, which only goes in one direction. Then we took data using three pins to figure out how light reflects off smooth surfaces.

Notice that I didn't get any words for the types of reflection; I finally remembered to do concept first, words second in this unit. Also, I realized too late to cut the little plastic mirrors into small pieces of make the lab easier and more accurate.