Flexi Says: Both diffusion and effusion are related to the speed at which various molecules move. Diffusion in gases (mixing) is nearly instantaneous. If you release a colored gas in a container of non-colored gas, the color spreads evenly throughout the container in a second or two. In liquids, diffusion is a much slower process. The smaller spaces to move through and the almost constant collisions cause the molecules to require much more time to move from one side of the container to the other.
