Over the last five years of teaching proofs in Geometry, I have learned two things: (1) the most effective student understanding comes from writing about their proof process, not from the proving itself, and (2) the most effective feedback process for students is a peer-to-peer reciprocal feedback process.
So this year, when I had to be out of school for a few days, I designed a Proof Portfolio project for them to do in my absence.
Each day had four small, reasonable proofs students had to do — and they could collaborate on these. But then... they had to write a number of short-answer reflections to analysis questions based on their own proofs in the day's set.
In addition, they had to find a peer to trade with and to give a rubric-based peer review and reflection.
In my class, they did this for several consecutive days. I made it worth a quiz/project grade.
It was clear that this project was a rite of passage for my classes.
But as I'm reading their work, I am blown away by how much they seem to have learned!
Their mastery of proof is not perfect. But it is authentic and it is growing. And to me, that is the most important point at this stage.
I made up four days' worth of activities. Each day is two double-sided pages (proofs & reflections).
Here is a link to the G-drive folder with the four PDFs: