Cartoons are an excellent way of simplifying complex ideas and adding humor. With a little effort, spatial, statistical, and structural relationships can all be visualized on an overhead. The projector is best turned off when the instructor is not directly referring to the overhead. Many instructors use a piece of blank paper to cover part of the transparency so that only the point being developed is revealed. It is also important never to leave a transparency on the screen so long that it becomes boring.
Video lends itself to classroom use extremely well.
It can provide a bridge between the abstract world of academia and the world of everyday reality. For example, in an English class a TA might show students a scene from a Shakespearean play. A political science class instructor may use a tape of a politician who visited campus, or whose remarks were broadcast on C-Span. A chemistry class may be shown a videotape of an important, but dangerous and expensive experiment. In a communication class, the students themselves could be taped during a problem-solving session so later they can analyze the group interactions that occurred.