Popcorn is a type of flint corn that has an incredibly hard outer covering. Popcorn pops because the starch inside the kernel expands and lets off steam, because of the hard outer coat the steam cannot escape. Pressure builds up and eventually the outer covering bursts, giving you the typical inside out popcorn.

Popcorn secret. Keep the lid off the pot until the first few kernels pop, this allows any excess steam to evaporate and leaves you with light fluffy popcorn.

It is critically important to ensure your popcorn is properly dry before trying to pop, moist or wet kernels will give you a bad pop. Finally clean all the silks out of your popcorn, the silks will burn leaving a bad flavour in your popcorn.

Popcorn being a type of Flint corn does make a pretty passable maize meal for pap, however the hardness of the kernels can put a strain on your grinder especially if it's a stone mill, steel burred mills will handle grinding popcorn a lot easier.