"They don't do spontaneous, once-in-a-life-time lecture to you." True, but you do vary presentation to allow for audience. I use 'room temperature' questions e

"They don't do spontaneous, once-in-a-life-time lecture to you." True, but you do vary presentation to allow for audience. I use 'room temperature' questions early on; rows of confused faces and I go into the slow siding; rapid fire answers and extensions and I shift into the express route. Mixed reactions and I have been known to split the whiteboard down the middle. So less a linear video tape and more a series of responses deployed depending on feedback from the class I am teaching below University level though, and smaller classes (15 to 25 people).