The document discusses the chemistry behind how popcorn pops. The three key things that allow popcorn to pop are moisture inside the kernel (water), starch inside the kernel, and the hard shell (made of cellulose) on the outside of the kernel. When heated, the water and starch inside try to escape but are trapped by the hard shell, building up pressure until the kernel explodes and expands into the light, puffy popcorn we eat. Unpopped kernels may result from weaker cellulose shells that cannot withstand the pressure. While popcorn is a popular snack, its production can impact workers' health and the environment if bags are littered.