I teach High School and we are on a block schedule (1:20 minute classes). Our warm-up exercise are daily drawings from observation done the first 10 to 15 minutes of class. Usually I set something on their desk, at the front of the room or have them pull something from their pocket. Last year I had the student buy a 6x9 sketchbook and if they didn't have one I supplied 6x9 sheet of paper. So I spend a lot of time cutting paper. They would turn them in after five class periods which would be about every two weeks and I would grade them, each drawing was worth 20 points. This year we made 9x12 sketchbooks and the students do all five daily drawing on the two page surfaces when the book is open. I didn't like the student drawing on the back of the previous drawing a first but it seems to be working out. At time the object they are drawing will be related to the current lesson and at time it won't. This is something I don't worry about to much. The only problem with this is I am not the best planner an
d many times I am scrounging around trying to find something for them to draw 5 minibus before class but I have a lot of junk in my classroom closet that I usually find something. Hope this helps.