"Would you like to see?" She offered a smile as she gestured to the little oven and the bag of salt. Then she walked over to the area. "Basically... heating up salt until it melts means the salt is really, really hot. The salt is so hot that the water instantly boils to steam.... As the water contacts the salt it dissolves rapidly, transferring its heat to the water much faster than would happen if the salt did not dissolve. So it sort of makes an explosion, even though technically it's not an explosion at all."