remember pop rocks? ever wonder how it pops like that? basically, they take an extremely hot hard candy mixture, mix into it carbon dioxide at 600 psi [pounds per square inch], and let it cool. as it cools it breaks apart, but a lot of the bubbles inside still remain. sometime later, when you put it in your mouth, the hard candy melts, and releases the 600psi bubbles of carbon dioxide which makes the loud *pop*. here's the patent for it held by general foods. Matt @ 10:19 AM