I'm just about finished watching the third of four lectures Richard Feynman gave at the University of Auckland in 1979. Besides being a fascinating overview of quantum electrodynamics for a general audience, it's wonderful to just see Feynman in action.
I'd always heard what a fantastic lecturer Feynman was and so I was keen to see him for myself. He was brilliant but not in the way I expected. He wasn't the most well-spoken person I've listened to; sometimes he would get a little lost in his train of thought, go off on tangents or start to say something only to decide not to proceed down that path; sometimes he'd make mistakes that he'd have to go back and correct.
So despite this, why were his lectures so good? A large part of it was his ability to extract out the key ideas of a theory and present them in a way that was relativity simple but still faithful to the full theory. This is true of his writings too. But what made his lecturing so good?
Four things come to mind:
His authority and his humility interacted in very interesting ways. Here was a man who was so comfortable with what he did and didn't know that he didn't need to boast. He could say to the audience "I'm not going to explain this because you wouldn't understand it" and not seem arrogant because he would just as often say "I'm not going to explain this because I don't understand it".
His humour was also remarkable; a combination of self-deprecation and genuine wit. When he made a mistake or decided to back-peddle a topic or example he had started, he'd always recover in a way that made the audience laugh.
But the thing that stood out more than anything else was his excitement about what he was teaching. You can tell, watching the video, that he just loved explaining this stuff to people. If I had to pick one thing that set him apart it would be that.
Even if you are not really that interested in physics, watch at least one of the videos just to see what a truly great teacher is like.