Sam Shah’s blog has been a veritable teaching clinic the last two weeks, more than filling his own installment of Great Classroom Action.
With Attacks and Counterattacks, Sam asked his students to define common shapes as best as they could – triangle, polygon, and circle, for instance. They traded definitions with each other and tried to poke holes in those definitions.
When the counter-attacks were presented, it was interesting how the discussions unfolded. The original group often wanted to defend their definition, and state why the counter-attack was incorrect.
Trade the definitions back, strengthen them, and repeat.
Sam created some very useful scaffolds for the very CCSS-y question, “If you have a shape and its image under a rotation, how can you quickly and easily find its center of rotation?”
This is an awesome exercise (inmyhumbleopinion) because it has kids use patty paper, it has them kinesthetically see the rotation, and it gives them immediate feedback on whether the point they thought was the center of rotation truly is the center of rotation. Simple, sweet, forces some thought.
Sam then pulls a move with a Post-It note that is a stunner, simultaneously useful for clarifying the concept of a variable and for finding the sum of recursive fractions:
Ready? READY? Flip. THAT FLIP IS THE COOLEST THING EVER FOR A MATH TEACHER. That flip was the single thing that made me want to blog about this.
Finally, Sam pulls a masterful move in the setup to his students’ realization that all the perpendicular bisectors of a triangle’s side meet in the same point. He has them first find those lines for pentagons (nothing special revealed) and quadrilaterals (nothing special revealed) before asking them to find them for triangles (something very special revealed).
There were gasps, and one student said, and I quite, “MIND BLOWN.”