 Soon they found that even students who had attended class reviewed the videos, including before exams.It was Sams’ idea to record all lecture and dedicate classroom time to questions, exercises and active lab work, which is the center of the notion of flipped classroom and the two teachers did so for the 2007-2008 school year for all their chemistry and AP chemistry classes.Class time became committed to working with students in areas of difficulty and active lab exercises.