academic books child education school student students teach teaching young backpack bag book elementary loaded primary schoolbag acadamic cognition göttingen knowledge library public research study studying blackboard board class classroom greenboard learn lesson pupils wall lesson one blue communicate communicating communication direction drop-off entrance exit inform information informing mobile mobility sign transport white words concentration desk learning people sitting table tables undergratuate undergratuates bookshelf bookshelves borrow desks educate lent lesen quiet read silence university warsaw