Review: Desmos

Desmos is a powerful online graphing calculator available on all current platforms. There is a good Quick Start guide:

Desmos is integrated somewhat with Google Drive. “Integrated somewhat”? The third-party Chrome apps are generally not integrated as invisibly as the built-in apps (Docs, Spreadsheet, Presentation, etc.). In the case of Desmos, the integration looks like this:

  1. Desmos appears as an option when you use the Create option in Google Drive; however, a blank Desmos graph then appears, with nothing created in Drive.
  2. If you want to save anything from Desmos, you need to log in. Desmos lets you log in with your Google account.
  3. You can save a graph you’re working on, but it isn’t saved to Drive by default. (It’s saved in a special set of Desmos files, somewhere in the cloud, associated with your Desmos account.)
  4. If you choose to save a Desmos graph to Google Drive, it is saved there as a PDF. You can print this PDF, but you can’t open it and make changes to it, or use it interactively.

The assignment

I wanted to immerse my Algebra 2 students in graphing parabolas. (This topic is directly addressed in the CCSS standard CCSS.Math.Content.HSF-IF.C.7a.) I had them graph some simple examples on paper using a few sample points. They were required to label the vertex and the axis of symmetry. They then took pictures of their work using the built-in camera on the Chromebooks; they pasted these photos into a Google Document.

I reviewed their work, leaving comments in the document itself. The next day, they used Desmos to graph the same parabola. They were required to paste the Desmos image into the document, after labeling the vertex and axis of symmetry. I moved their final documents into a read-only folder and added a final comment with their overall rubric-based grade.

Working with Desmos in Google Drive

Each application (non-Google and Google) has a slightly different way of handling exports and imports. Once you’re logged in to Desmos, a Share Graph button appears in the toolbar at the top. There are four different export options, three for sharing the interactive graph itself (using a short URL) and one for sharing an image.

I asked my students to export the image. It then appears in the Downloads folder in the Files app. In their original document, they then used Insert Image | Upload to select the image from Downloads.

Desmos does not provide a way to add text to a graph, so the students were left to figure out for themselves how to do this. I envisioned them using Google Drawing, and most students did this, “crowd-sourcing” the solution. They pulled the PNG file created by Desmos in their Documents folder into Drawing, added the text, saved the Drawing, and imported that into their Google Document (using the web clipboard). A few used the third-party app Pixl Editor for its greater capabilities.

The screenshot below demonstrates my commentary, the graph itself (annotated by the student), and a file-naming convention.

Screenshot 2014-01-02 at 8



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