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Pinhole. Gas. Vacuum. Pinhole. Gas. Vacuum. Diffusion vs. Effusion. Diffusion - The tendency of the molecules of a given substance to move from regions of higher concentration to regions of lower concentration Examples: A scent spreading throughout a room
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Pinhole Gas Vacuum
Pinhole Gas Vacuum
Diffusion vs. Effusion Diffusion - The tendency of the molecules of a given substance to move from regions of higher concentration to regions of lower concentration Examples: A scent spreading throughout a room or people entering a theme park Effusion - The process by which gas particles under pressure pass through a tiny hole Examples: Air slowly leaking out of a tire or helium leaking out of a balloon
Effusion Particles in regions of high concentration spread out into regions of low concentration, filling the space available to them.
Weather & Air Pressure HIGH pressure = good weather LOW pressure = bad weather
Weather and Diffusion LOW Air Pressure HIGH Air Pressure Map showing tornado risk in the U.S. Highest High
Hurricane WilmaOctober 19, 2005 88.2 kPa in eye
NET MOVEMENT To use Graham’s Law, both gases must be at same temperature. diffusion: particle movement from high to low concentration effusion: diffusion of gas particles through an opening For gases, rates of diffusion & effusion obey Graham’s law: more massive = slow; less massive = fast