We have learned over the past few weeks that gases have real-life constraints on how they move here in the non-ideal world. As with most things in chemistry (and also in life) how a gas moves is more complex than it at first appears. In this episode, Hank describes what it means when we talk about the velocity of a gas - to understand gas velocity, we have to know what factors effect it, and how. Hank also teaches you about effusion, diffusion and concentration gradients, before showing off a cool experiment that physically demonstrates the things you have just learned. Sound exciting enough for you? Let's get started. *Special Thanks to Matt Young at the University of Montana (Geosciences Department, Environmental Biogeochemistry Lab) who helped with the chemical demonstrations.* Table of Contents Net Velocity vs. Average Velocity 1:17 Effusion 4:47 Graham's Law 5:52 Diffusion 7:22 Concentration Gradients 7:08 Precipitation Reaction with Gases 8:21 -- Want to find Crash Course elsewhere on the internet? Facebook - www.facebook.com/YouTubeCrashC... Twitter - www.twitter.com/TheCrashCourse Tumblr - thecrashcourse.tumblr.com Support CrashCourse on Subbable: subbable.com/crashcourse