The Combustion of Lycopodium Powder
Lycopodium powder is squeezed from a squirt bottle into a candle flame, and is shown to be readily ignitable. Another portion of lycopodium powder is poured to form a small mound on a watch glass. A match is touched to the pile of lycopodium and, to the surprise of the class, fizzles a little, but never completely combusts. The candle is then set onto the ground and lit. A long cardboard tube is set over the candle, and lycopodium powder is dropped into the tube from a notecard. A small explosion occurs and flames shoot from the top of the tube.
Lycopodium powder is made up of waxy spores from club moss. It was once used as flash powder in early photography. When the powder is squirted into a flame, much of its surface area is exposed to the oxygen in the air and is readily combustible. The surface area exposed to oxygen is greatly reduced when the powder is in a pile, and only the grains on the surface of the pile will ignite.