I have posted in this blog about how the chemical and physical characteristics of an element can be dramatically altered by other elements with which it combines. A case in point is sodium chloride (table salt), which is an innocuous chemical. However, as the video from the BackyardScientist below demonstrates, molten sodium chloride can be quite explosive when added to water. However, this reaction seems to be a physical reaction not related to the explosive properties of elemental sodium. It may have to do with the way the water is heated and converted to vapor very fast within the blob of the molten salt as it goes under the surface of the water.