Looking Smart

So I caught myself explaining what I know about physics to a friend today, and it struck me that it felt like I was trying very, very hard to look knowledgeable. In the Tao te Ching, Lao Tzu said, "(S)He who speaks of a thing does not truly understand it."

Paradox aside, how can one explain something to someone without looking smart? That is, how do I explain physics to someone who isn't versed in it in such a way that it sounds like anyone could do it, instead of an intellectual elite?

>>12
Get out.

I have the same problem.. except the things that I try to explain can't be explained without using physics jargon or big words in general.  I get "You're the smartest person I know" deal all the time, and it pisses me off.  If I'm the smartest person that they know, then that doesn't say much for everyone else.