PURPOSE: Simple model of Brownian motion.
DESCRIPTION: The small pucks represent air molecules, which chaotically strike the larger smoke particle, producing irregular motion of the smoke particle. Be careful with this model, however: in reality, because of the enormous size of a smoke particle relative to the size of an air molecule, it takes a net of about 10^4 molecules of air on one side relative to the other side of the smoke particle to make it change its motion noticeably. Many people overlook the statistical basis of Brownian motion, and believe incorrectly that a single molecule of air might be able to noticeably change the motion of a smoke particle.
REFERENCES: (PIRA 4D10.20)
EQUIPMENT: Air table with lots of small pucks and a larger "smoke particle" puck.
SETUP TIME: 5 min.
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