Today, the future physics teachers and I will tackle projectile motion with metersticks and protractors. I’m curious how this will go.

## 3 thoughts on “Projectile Motion…”

1. ljatkins says:

This looks awesome – but also hard to do well! – I’ll be curious how it goes. Are you constructing parabolas from rules or using parabolas to … no, must be the first. That’s really cool.

Quick question – do you do any SBG this semester? If not, why the switch? If so, how is it showing up (particularly in inquiry)?

2. Right, I don’t assume a parabolic shape. I only assume that the velocity vector needs to be updated by a downward “10 m/s” every second. Then I can update the position one of two ways… by noting that the average velocity will fall right in the middle of the two velocities, or by figuring out how far it would have gone without gravity and correcting that by a factor of 1/2gt^2. If I keep doing 1 second updates… then average velocity vector = displacement, or 1/2 g t^2 = 1/2g. If I don’t, then I just need to scale the average velocity vector by the number of seconds, or scale 1/2 g by the square of the time.

So far, I only do SBG in my intro physics course, mostly for the things that I control grading of, which is quizzes and labs, but not exams. Its been a changing process every semester. I already plan to do it differently next semester.

I don’t do it yet in inquiry, but I’d like to. It’s just harder to wrap by brain around it with responsive teaching, emergent curriculum. I have to be much much better at articulating my goals for the course, and what will count as evidence that students are mastering them… Grant Wiggins is whispering in my ear to pick up “Understanding by Design” again…

3. I will add that for one student, doing projectile motion this way was highly *transformative*. He went home and made some very impressive diagrams on really large butcher paper. Its up there as “highly braggable” work. Since then, he has said things repeatedly about how learning this has impacted him, including changing the way he thinks about projectile motion, and wishing that we learned more things like *this*. (What *this* is, I don’t know). Beyond that, he has been sharing this way of thinking about problems with others, and has decided for research (thesis), he wants to research something about teaching/learning projectile motion this way. Crazy.