Guesstimation: solving the world's problems on the back of a cocktail napkin

Physicists should be able to estimate anything, starting from the laws of physics and few simple numbers. This talk will present the general rules of estimation, the Goldilocks categories of estimates, and many examples, including the number of people picking their nose right now, the reasons we drive gasoline rather than electric cars, how Fermi estimated the magnitude of the Trinity atomic explosion, the dangers of traveling to the center of the galaxy, and the most commonly asked environmental question of our time, ``Paper or plastic?''