From the article "One person (the presenter) is presenting information to other people (the audience). The flow of information is one way, from the presenter to

From the article "One person (the presenter) is presenting information to other people (the audience). The flow of information is one way, from the presenter to the audience. Because the flow of information is one way, the presenter can and does script out the entire presentation ahead of time, much like a movie or a novel. Like those forms, a PowerPoint presentation is highly linear. It is meant to be experienced in a particular order. Deviating from the expected order is possible, but awkward." It takes way too much effort to create a linear presentation for a class, especially while pre-requisites are missing. I've had this situation while teaching mathematics. Two people in the class didn't understand negative numbers. When you're using a pen and a whiteboard, you have the freedom to draw a number line, spend one minute explaining negative numbers and then continue.