Products of the reaction between magnesium and dry ice (solid carbon dioxide). The top block of two blocks of dry ice is removed to reveal the products of the reaction between magnesium and carbon dioxide. The dark powder is elemental carbon. In this demonstration, magnesium turnings on a block of dry ice were ignited, and another dry ice block was placed over the top. An exothermic displacement reaction occurred where the magnesium displaced carbon to form magnesium oxide and elemental carbon, seen here. See K004 4912 for the reaction.