A friend of mine attended a private school in Nashville, and one of his chemistry teachers may well have become a Darwin winner by now. She told the class one day that salt is made in factories, to the disbelief of most of the kids who knew that salt is mined as a natural mineral.
Teachers hate to be corrected.
Andy asked if she could provide a practical demonstration, but no sodium was available. So he suggested that creating another salt, such as potassium bromide, would be close enough. She sent him to fetch elemental potassium and bromine from the chemistry lab. He also took the liberty of turning off the electricity and gas supply to her work station, just in case, then returned to the classroom with a plastic tub, a bottle of bromine, rubber gloves, tongs, and a half-pound block of potassium. Andy placed the tub in the sink, poured in the bromine, and handed the other items to the teacher.