The Art of Presenting

As part of my physics courses, my students are usually required to perform a powerpoint presentation about a course-related topic that they find interesting.  As harmless as it sounds, the very idea of speaking in public induces fear in many of my students.  While I do sympathize with them, these presentations remain a part of my courses because (1) oral communication is an important skill, and (2) I feel that if you cannot communicate what you have learned, you have not learned it.

Jerry Seinfeld once observed that the number one fear of most people is public speaking, while number two is death.  He went on to muse that, at a funeral, the majority of people would rather be inside the casket than giving the eulogy. 

What is it about giving a presentation that is so scary?