I bet the famous Nick Coleman. . .

. . .didn't know this (from Ldotter Remington):

Popcorn "pops" because the moisture within the kernel turns to steam. Properly conditioned popcorn is about 14% moisture by weight, and this is the secret of larger naturally aspired corn popping. Decreasing the pressure under which the popcorn is popped accentuates the pressure differential inside and outside of the popcorn hull, allowing for a fuller and more complete "puff" when the hull bursts.

I'm always finding out cool stuff like that at Lucianne.com.