A little low-tech ... I use whiteboards a lot in class - fortunately all of my walls save the windows are covered in whiteboards. Typically all of my students (~20) are up at the boards for at least part of each class and occasionally for the entire class. For example, today in my MCR3U class I put trig identities to prove on slips of paper and had partners pull one and solve it on the whiteboard, pasting images of the whiteboard solutions in our class OneNote (and then they pulled another question from the pile). What we need, though, is a way to clean the boards off quickly between questions. Now, we don't have a whole bunch of whiteboard erasers (they are costly, for sure, and plastic -- we don't have our own classrooms so every teacher would have to bring 10-20 erasers around with them) so I have always been looking for alternatives. Things I've tried: Old towels. I would rip them into squares. They work really well but they went missing all the time. In part,...
...not something ready-made, but something in continuous formation through choice of action. J. Dewey