Large number of small particles all in rapid motion Kinetic Molecular Theory What are the properties of Gases?  (5) Can fill any container Can undergo Diffusion and Effusion Can be compressed Have low densities Are fluids Movement of particles flowing through hole until the molecules reach equilibrium Diffusion According the KM model which moves the slowest in which phase? Solids Why do high altitudes have less pressure? It is further away from earth and pressure lessens from further away A common device used to measure atmospheric pressure is a.... Barometer