He may be the Most Important Theoretical Physicist Since Einstein, but Stephen Hawking has not Lost his Touch in the Classroom

Like any good teacher, Stephen Hawking knows he has to grab his students' attention and hold on tight.

That isn't easy when your field is theoretical physics. It's even harder when you are paralyzed and must use a machine to talk.

But Hawking succeeds, with the aplomb of a seasoned comedian who knows how to work an audience.