Soft percussion and a toasty scent mark the violent transformation of tough seeds into cloud-like puffs. This is the almost magical process of popcorn-making. Dozens of kinds of popcorn are now grown in the US, with different strains assuming distinctive shapes when their kernels explode. So, how did we actually end up with this whimsical food? Andrew Smith traces the history of popcorn. Lesson by Andrew Smith, directed by Mitchelle Tamariz.