Whoa! I’m not a fan of the class days where I have to do a lot of talking and explaining. The students get bored, everyone gets restless staying in their seats. The discussion was totally worth it. First, we asked the students to draw something fast and slow. We got a lot of fast race cars and very slow snails. Then, I asked about what their motion maps would look like, and we added it on.
After discussing what it meant to be fast or slow, we talked about what it measured. They all agreed that it measured a speed. So when I asked them what “speeding up quickly” or “speeding up slowly” looked like, we got a variety of answers.
In this first picture, students wanted to outdo their classmates and drew a graph instead of a motion map or whatever else. So they drew a position-time graph that had a horizontal line that represented fast, and one with a slope that represented speeding up quickly. When we presented, the other students didn’t seem to think there was anything wrong with their thinking…because they all thought it was right. One group, however thought that it was wrong, but they just didn’t know why. After more arguing, a student raised his hand and finally said what this picture meant.
There was a group of girls that are really active in participation. They showed us their board, and although when I first walked around, it looked fine, when it came time to present, there were so many errors.
Before I took the photo, the student erased what she wrote for Fast because it was wrong, even though I encouraged her to just correct it in a different color. For the line “Fast,” they drew the same sized arrows with different velocities written on top. So it seems that the students substituted time values with velocity. Underneath, speeding up quickly meant that the increase of speed increased with each second. Rather than increasing speed at a constant rate, it increased speed at an increasing rate. That was really hard for me to explain how it was not acceleration (open to feedback!).
A group that was very quiet throughout the whole discussion thought something different. During the “speeding up slowly” discussion, they showed me what they drew. Some of their classmates looked at it, but were upset at their drawing (mostly because we haven’t done something like it yet, and they had a really good answer). Then the rest of the groups started to think that if I’m speeding up, then that means my velocity is changing!…and then we started drawing v-t graphs that showed a constant change.
For Block 5, my block with the most energy, a team of teachers came in to observe another classroom. My students were convinced that they were there to observe the students and maybe “tell on them”? I have no idea. But no matter what I said, they didn’t seem to believe me that the teachers were there to observe me and the classroom, not their individual behaviors. I assigned an algebra-heavy homework assignment and a reading to go with Acceleration from Physics Classroom.