Carl's Teaching Blog

A place to talk about teaching and learning

Clog: Launching the #ThinkingClassroom again

So my thinking classroom may have just given the best math class interactions I’ve ever had. More on that later. First let me get up to speed with this experiment.

Last cycle I had a good experience with the Thinking Classroom. I’ve written a few blog posts about it, including one about my plans, another about my awesome and excessive randomizer, and another about kids taking notes. The experiment ended in January because the marking period closed, but I decided to reboot it with a new kids on a different schedule. It’s really great having a second chance to go over the norms with a fresh group and get more practice on-boarding them. Having a bank of problems to use is an added bonus. So far, we have been doing  visual patterns, including my new favorite visual pattern lesson for VNPS, which I could write a whole other post about. (Actually, I’ll just write it now. This lesson has lots of patterns, you can cut them up into strips and give different linear and quadratic patterns to different kids. Give them to different groups and then have them walk around and check out the patterns that the other kids worked on). My classes on this schedule are an hour and a half long, and the VNPS seemed like it would be too long for that, so I have been doing Desmos activities in the remaining time. As the class comes to an end I’ll have kids work on using Desmos to make models of data that is important to them.

Today we used a different shell center problem and it just kept on giving. I showed the kids this prompt and asked them to think about how many would be int 30cm x 30cm and the 40cm x 40 cm and an equation.

The kids ended up doing a lot of thinking, including two students who weren’t here for the first cycle. Two of the three groups got to an equation after 45 minutes, but one group defined the 20cm case as n=1, while the other made an equation where n=20. This was led to a great conversation that we have been having about equivalence, but also about this thread of what I guess I would call “Mathematician’s License,” (like “poetic license”) One of the groups was trying to convince themselves that they had done it wrong, and I had to stop them and say “You made an equation the describes this situation, and that group did as well, and they aren’t the same. That’s ok. In fact, that’s what mathematicians do!”

All the groups seemed only 80 percent clear on the problems, so I made an extension question. I asked the kids about the 20cm x 30cm rectangle and they were all able to think about an equation, and no one’s equations were the same. The two groups from above actually tried solving it using the other groups value for n! It was great to see ideas spreading around the classroom. All the kids were supposed to sit down to work on the Desmos activity, but those two groups kept lingering around their boards. One group had a functional equation and they kept working on the ways to ‘simplify’ it. The other group was struggling a little with their equation, because they wanted to figure out how to write it so that it could apply to rectangles of any size!!!! I was shocked that a kid would even ask that. I told him that we would probably need some multivariable equation to try and figure that out and he was like “are we going to do that this cycle.” What!?!!? I had to restrain myself from not nerding out because we needed to get to work on the Desmos activity. I’ll say this is the first time I’ve ever had a student linger around and do more math, let alone ask me to do more. I think it shows that the kids have built up a lot of confidence and ownership in the first 4 days of the class.


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  1. What an encouraging story. I love how the context naturally promotes the idea of generalization and the learners ran with it. Some of the teacher moves I’m interested in are how you’re allowing them to leave the negative self-editing that they picked up from previous math classes. Where an answer wasn’t sufficient, you had to have the teacher’s answer.

    • c2cmathed_webmaster

      Thanks for the reply! I think the students are still doing some of that, but because they are working on groups they are also accountable to each other so it’s hard to sort of ‘freeze up’.

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