Why do Rice Krispies go “Snap, Crackle, Pop?”
Rice Krispies are made by steam cooking rice kernels in such a manner that each kernel fills with tiny bubbles of air and puffs up.
These puffed-up kernels are next flattened and roasted until they become crisp. When milk (or basically any liquid) is pored over the Rice Krispies, each kernel gets wet and starts to swell unevenly. This causes the crisp portions of the kernel to give way and break with a snap, crackle, and pop.