DESCRIPTION:
In this demo, camphor particles are placed in water. They sublime at room temperature which is why camphor’s odor permeates the room so quickly. The gas that forms around the particles propels the particles in random directions. Earwax contains a large percentage of long chain fatty acids which form a monolayer in water, thus ceasing the motion of the camphor particles.
TOPICS COVERED:
– sublimation
– monolayers
– physical change
MATERIALS NEEDED:
– 2 small petri dishes
– camphor
– scupula
– water
– overhead
PROCEDURE:
1. Place the petri dishes on the overhead, and add enough water to cover the bottom
2. Place some camphor in each dish
3. Wiggle your finger in your ear to get some wax, then place it in one of the petri dishes
ADDITIONAL COMMENTS:
Camphor has a strong odor; it is what gives Vick’s Vapor Rub it’s scent.
SAFETY:
Safety goggles should be worn at all times.
REFERENCES:
Wightman, James. Personal Interview by Kevin Caran. 01 Jul 2010.
Okuda , I. B.; Bingham, P. S.; Hawke, M. “The organic Composition of Earwax.” Journal of Otolaryngology 20.3 (1991): 212-215. Web. 15 Jul 2010. http://www.ncbi.nlm.nih.gov/pubmed/1870171