Once everything is setup the experimenter places a chunk of magnesium on a block of dry ice.  Notice it is in a protective see through area with some type of heat resistant glass or protective barrier.  The science teacher proceeds to make a few jokes about the volatility of such an experiment and takes a blowtorch and lights the magnesium.

Once the science teacher lights the magnesium on fire, he puts another block of dry ice on top.  It makes carbon dioxide gas and magnesium oxide and elemental carbon as biproducts according to the experimenters.  The carbon is noticeable at the end as a dark grayish material that almost looks like a bunch of pencil lead.  That would make sense since graphite is composed almost entirely of carbon atoms.  Writing with graphite is a lot easier so that is one way you could tell if you did not know what materials were there 😉

Be safe, only experiment with professionals in a ventilated and proper lab environment.  We hope you enjoy this video..