Back to blogging with my best class ever
I’m sorry that I’ve neglected this blog for so long. I’ve got so many drafts stored away that I need to finish, but too much has been going on to find the time to write.
But today, I have to write, even if it means I’m doing it in the middle of the night.
I just had my very best class that I’ve had in 15 years of teaching. And thankfully, I have it all on tape so that I can remember it.
I have this really dumb habit of tearing up in the classroom when things are going really well, and today, I was almost wiping away rivers of tears at the end of class.
We were working on the same BFPM bridging activity that I’ve written about before, but this time, we made a few more modifications. We felt the old activity forced the students to wrestle too much with what was going on when the box was accelerating, particularly since we haven’t studied acceleration or unbalanced forces, so we modified the assignment so that students wouldn’t consider the times when the velocity of the box was changing. Here is the revised activity as a pdf.
At first, I was a bit reluctant to make this change, since in the past, students ultimately were about to come to good conclusions about the accelerated portions of the motion. But I was totally convinced when we tried this out in class—by reducing the complexity of this task, we allowed them to build up more confidence, and piqued their curiosity, so that they naturally wondered and asked great questions about what was happening in the accelerated phase, with out getting bogged down with all the details.
One other thing I’ve been doing this year that I think is starting to pay big dividends is giving short metacognative lessons. I’ve had students complete a couple of assignments on canvas where they respond to articles about feedback and why it is good to fail on assessments. I’ve also tried to take a minute or two here or there to talk specifically about how they are discussing ideas in class and offer suggestions for how we might continue to improve. Today I asked them to focus on speaking to one another and making sure they were involving everyone in the conversation.
And here is what I got (they are working on the second page of the activity when this starts).
I hardly have to speak at all. These are students who just figured out N1L two days ago. At around 8 minutes I step in and push them to think about what’s happening when I push on a box at rest. They have a great discussion, build up lots of confusion, and then are totally happy with putting this question aside and moving on to the next part of the activity.
So we move on to the third page—and they just nail it, which is pretty much to be expected. But even when I push them on giving multiple ways to explain how to test that the puck is moving at constant velocity, they do it.
Now, here’s where I think it gets really good. In the 4th page, we get them to think about a situation where you are pushing the block first at a constant slow speed, and then later at a constant fast speed. They do a great job of discussing this, checking their work, and collectively, they all come to the wrong answer that when the box is moving faster, you are pushing harder. All I have to do is tell them they are collectively wrong and they should check their assumptions, and they come back with two amazing explanations:
- Maybe friction doesn’t depend on speed
- Or, Maybe N1L needs to be modified—perhaps CVPM doesn’t mean Fnet=0.
The points they raise in discussion here with minimal assistance from me are stunning to me. They even get to the point where they figure out that they need to settle this with an experiment, and they do this. All of this is stuff I used to simply walk classes through in the past.
Now, they talk about the result of the experiment, and use it to definitely answer the 4th page of the activity, and along the way they come to so many more realizations—FBDs don’t tell you the velocity of an object, other things the frictional force might depend on, the threshold nature of the static frictional force, how drag forces depend on velocity, and much more.
Even though I’m amazed by all these students did today, in watching the video, I see few of them are taking notes, and it makes me wonder if many of the insights we realized today might be ephemeral, and wonder what I can do to help them preserve the understandings they came to today.
And, this is 80 solid minutes of discussion. Students are whiteboarding in parts, and we do some experiments, but I see some yawns, and certainly not everyone is engaged at every moment. I can also tell this is mentally exhausting—it makes me wonder what we can do to help students be more engaged in discussions like this.
And in the last segment, I’m doing quite a bit of leading—I wonder if I’m going to be able to find a way next year to turn even more of that over to students. If I do, I think I’m going to need to remember to bring a box of kleenex to class.