WHY RICE KRISPIES SNAP, CRACKLE AND POP! – Rice Krisipies, also known as “Rice Bubbles” in some countries, are created by preparing rice in such a way that it will “pop” like popcorn during the cooking process, albeit much less dramatically. This popping puffs up the kernels. When the rice is finished cooking, most of the Rice Krisipies will have thin, solid walls with hollow, sealed areas inside where air pockets have formed. When cold milk is added, the sudden temperature shift causes the walls of the air pocket regions of the Rice Krispies to fracture suddenly, making a snap/crackle/pop type noise.