CNN.com - Scientists solve unpopped popcorn - Apr 21, 2005

"Scientists solve unpopped popcorn
To pop or not to pop lies in the hull


INDIANAPOLIS, Indiana (AP) -- Eat your way to the bottom of almost any bag of popcorn and there they are: the rock-hard, jaw-rattling unpopped kernels known as old maids.

The nuisance kernels have kept many a dentist busy, but their days could be numbered: Scientists say they now know why some popcorn kernels resist popping into puffy white globes."