What exactly makes popcorn pop? Normally, you make popcorn by either heating a prefilled bag in the microwave, or putting some kernels in an airpopper, both of which heat up the kernels of corn until they explode. But why do they explode? Popcorn is unique because it has a really strong outer shell and a perfect mix of water and starch on the inside. As the kernel is heated, the starch melts and the water gets converted into steam. And eventually the pressure causes the shell to crack and all of