Last year I opened the door to a conversation about proof by adapting an activity from Max Ray-Riek over at the Math Forum. I asked my Geometry kiddos to write out directions for how to make a Peanut butter and jelly sandwich. I swapped directions around somewhat randomly and asked the students to do their best to make a sandwich only following the directions given. It is a fun activity, the kids get a laugh out of it and we have some yummy afternoon snacks. Most importantly, I think that it makes a vivid point about how detailed you need to be at times when trying to tell someone how to do something. I will use this conversation and activity as a reference point over and over in the next few weeks as we begin to grapple with what it means to prove something and how you can explain to someone why you think that something is true. I took a few photos of the sandwich designs that I want to share here. In the first one, try to notice on the paper how scant the directions were. Last year I had such a thorough and detailed description written by one of my students that I posted her PDF document here on the blog. I have yet to dig through all of the directions that were turned in this year, so I do not know if there is a winner in that category again this year. Here are some of the fun photos from the day.