Everyone knows that table salt is sodium chloride, but many people don't know about the explosive power of metallic sodium. Back in high school chemistry lab, when the teacher wasn't around, some of my fellow students and I sometimes flipped a tiny chip of metallic sodium into a bowl or water. The sodium would spin in flames and burn out as it is converted to corrosive sodium hydroxide. This unusual video demonstrates what happens when you throw a huge roll of sodium in to a lake.