I’m excited to share this really successful activity – perfect for Algebra 1 students! You’ll see in the below writeup how using Desmos and Pear Deck made this difficult task not only doable but also fun. This activity teaches students how to write equations of lines with a restricted domain.
Preview of Desmos portion of activity where students use movable points to visualize how to write equations of lines
One of my colleagues (Jeff Bellestri) and I teamed up to create an engaging and fun way to teach 9th grade Algebra 1 students how to write equations of lines. Since students would be completing this activity the day before winter break, we decided to give it a holiday theme. My goal was to incorporate technology to create a healthy sense of competition and collaboration among students. As you read through the activity students completed, you’ll see how tech enabled students to visualize the process of writing linear equations and also required the participation and attention of every student in the classroom.
Going into the lesson, students already knew how to graph a line given its equation, but they had only just begin working the other way around—to write an equation given the graph of a line. The ultimate goal for this exploration was for students to come up with equations for all line segments making up the holiday tree below:
To complete this task, students needed knowledge beyond what they had learned. Though they couldn’t have completed the activity on their own, by guiding students through an active step-by-step exploration, they were able discover how to apply prior learned knowledge to execute the task at hand.
We used Pear Deck to engage all students in the initial exploration—how do you write the equation of various line segments (lines with a restricted domain)? Pear Deck is a teacher presentation tool that allows for real-time formative assessments, so it was the perfect thing to engage students in the process of discovering how to write these equations.
We began with something easy, the horizontal line pointed out in the screenshot below:
Using Pear Deck, students saw this image on their laptops and individually typed in their responses. After all students had submitted a response, we displayed the results of the class on the projector. There is great benefit in reviewing and discussing the results of the whole class. This enables the teachers to talk through why a certain answer is incorrect and to immediately address popular misconceptions. The problem that we typically run into when reviewing work on the board is that a student might feel ashamed of an incorrect answer. Pear Deck keeps these results anonymous, a point that’s very important to me. In an exploration, students should feel safe. Trial and error is an important part of the learning process. Students learn at different paces and technology can be an incredible tool to help differentiate the classroom.
The second step was to begin exploring domain. Since the blue line making up the base of the tree is only a line segment, we need to restrict the domain of the function to appropriately control its bounds. Students were asked to drag two red, vertical bars to explore this question: