The class had been working on exploring right angles in pairs. I summarized what we had done, then invited them to consider what they had discovered about angles, and specifically, about right angles. My question was phrased thus: “As you and your partner worked with the geoboards, and recorded your work on dot paper, what did you discover about angles?”
The question was open ended, yet specific enough to guide their thinking towards the intended lesson outcome (an understanding of right angles).
Happily, the effect was what I hoped for. Much richer understandings emerged, as one student noted “right angles are like part of a square”, and another quipped, “when a diagonal line meets another line, that is NOT a right angle”. We did have to spend some time clarifying the difference between “straight” and “horizontal” (namely, that they are not synonymous!), but overall, the “What we learned” section of the lesson board was far more fulfilling today than during previous lessons.
I will try again tomorrow to be intentional, as we begin to describe polygons in more detail.