Column chromatography is a purification technique in chemistry used to isolate compounds of varying polarities. A glass column with a stopcock is first filled with a small amount of filter (usually glass wool) then a stationary phase such as silica gel, and then something to level off the top of the stationary phase such as sand. The mobile phase is an eluent added to the stationary phase until completely wet. Then the organic compound in solution is added to the stationary phase, and the eluent is added consistently to push the organic compound through the stationary phase. This separates any impurities in the organic solution by the principle of varying polarities. Flash Column Chromatography simply makes the process much quicker by pressurizing the column, usually with gas like nitrogen, in order to make the mobile phase run through the gel faster.