Burning magnesium in dry ice

Magnesium's reaction with carbon dioxide is a dramatic and beautiful demonstration to show that oxygen isn't always a prerequisite for fire and to reveal carbon's place in the reactivity series.

Displacements appear at the heart of the chemist's toolkit for exhibition reactions. Surely just about everyone has, at some point, put pieces of metal into test tubes containing solutions of metal salts and used the reaction (or lack of) to produce a reactivity scale? Most students also get to see how dramatic and useful this kind of chemistry can be when they watch the thermite demonstration. From there they'll go on to look at the production of iron in the blast furnace and they may even reduce iron themselves on a match head. Having spent time talking exclusively about the reactivity of metals however, it can seem rather odd to throw in carbon for our convenience at this point when students haven't had any tangible experience of it. This demonstration bridges the gap very nicely.