Susan Yochum from Seton Hill University, Greensburg PA sent in photographic proof of the effects of surface area on a combustion reaction. The dramatic result of spraying lycopodium powder through the flame of a candle is captured in the photo! Lycopodium powder is a fine yellow powder made from the spores of the lycopodium plant which is a small pine that grows low to the ground. The powder is commercially available from various chemical or science education supply vendors at a reasonable cost. Luckily the plant grows in the woods of western Pennsylvania so Susan can bring in a sample to show her students.
Susan noted that if one places a small amount of the powder on the end of a spatula and holds it in the flame, the lycopodium does not ignite. However, when the powder is sprayed through the flame, the powder ignites producing a tremendous flame due to the increased surface area. Students agree that this is an enlightening demo that enhances their understanding of the impact of concentration and surface area on reaction rates.
Observers should stand at least 10 feet from the demonstration and wear safely goggles. The teacher should follow all safety considerations when working with a combustion reaction in class.