I always like to keep on moving in class as I lecture when not using a PowerPoint presentation. The students keep their eyes on me and their attention as well. In the beginning of class, I give all students the ability (using a rubber spider, which is passed along), to call on another student for discussions by engaging that student into the discussion and this helps with the flow as well. So constant movement in the classroom is necessary as many feel that 'academics' is a place where they can fall asleep and relax outside of the lab environment. ~Louis