This awesome little chemical machine is from Mr. Kent’s chemistry page. Ice is laid in a Pyrex dish over a layer of calcium carbide. As the ice melts, the liquid water reacts with the carbide to produce acetylene gas, which of course is highly flammable. A match starts it off, and then it burns continuously on its own. My first thought was that the system could rapidly spiral out of control–more heat melts more water makes more gas makes even more heat. But it’s limited by the amount of oxygen that can get down into the pan, I think. My second thought was that maybe a bit of sodium metal down there with the carbide could make the process self-igniting…. (For God’s sake, no one try that.)