Why do we eat popcorn at the movies, and when did that start? On my America Weekend show, I turned to an expert for answers: Andrew Smith, author of “Popped Culture: A Social History of Popcorn.” I asked him how profitable popcorn is for movie theater operators, why the business took a dip in the 1950s and 1960s, whether popcorn is as popular around the world as it is in the US, and more. Listen to our conversation here.

Warning: the music I used to begin this segment will be impossible to get out of your head, like the shell of a popcorn kernel stuck between your teeth with no toothpicks around.