Nitrated cellulose is ignited to show its rapid combustion due to the presence of extra oxygen atoms in the molecule. Then its use as a propellant (expanding hot gases while burning) is illustrated by placing a couple of pieces of guncotton in a thick cardboard tube with a short visco fuse. A small ball made out of wood was used as the projectile. This was pointed safely towards a plastic screen/blind that absorbed most of the shock.
