I first heard about Desmos on Twitter. What an incredible graphing tool. I don’t think any teacher forgets the first time he/she introduces desmos to the classroom; you can feel the room buzzing with excitement. Just amazing. So every year I look forward to the day I introduce my students to graphs and Desmos.
Unlike a lot of physics modelers, I do take the time to go through “unit zero” (scientific reasoning) with my students in Introductory Physics. Perhaps the reason is because I like the development of the linearization concept in graphs (very useful for my IB students), perhaps it’s because I like to kick off the class with the spaghetti bridge lab, or possibly it’s a combination of both. The funny thing though, is that every year I introduce students to graphing in a different way, and I’m always uncertain of the best way to do it. While I have had students produce graphs by hand, I always questioned the validity of hand-drawn graphs in the digital age. I have also tried digital tools like:
- Excel (too complicated for most students)
- LinReg (good but not very flexible–students also have to download the program)
- LoggerPro (love it but there is a learning curve–school/student must have a license)
- Desmos (Free and very user-friendly)
This year I decided I was going to let students choose whatever method/tool they prefered for graphing, but I was only going to use Desmos when answering questions or showing solutions on the board. Of course I didn’t have to sell Desmos too hard for students to start adopting it.
In my experience, Desmos really excels in helping students do curve fitting. The way students can interact with graphs is incredible. Before students learn how to make graphs and before best fit lines magically appear on a screen, Desmos helps them understand the basic mechanisms of manual curve fitting. So I gave them a set of problems where the objective was to graph the data, linearize it if necessary, and come up with a mathematical model (equation) for the relationship between variables. The purpose of the linearization step is to help find the mathematical model and aid with the analysis of data (which wasn’t part of the assignment). The thing is, with the help of slides in Desmos, students were able to come up with the correct mathematical equation without much trouble and without taking the extra linearization step–the “test plot.” This is when I started rethinking linearization. I wasn’t fully convinced that students were getting it, and I pushed them towards creating a linear plot. Confusion soon emerged. Students weren’t sure why they were trying to produce a linear plot. It took me a couple of hours to straighten things out. Here is an example of the problem I asked my students to work on and the graph made with Desmos.
Right now I’m thinking that maybe next year I’ll skip unit “zero” altogether and introduce the topic as it comes up in other units. And instead of talking about linearization, I’ll just let Desmos do its magic. I don’t know how that’s going to pan out, but I think it’s worth a try. The only thing I’m sure of is that Desmos will once again be the gateway to graphing in my class.