The clumping factor is a measurement of how density varies within a gaseous medium, and is commonly used in astrophysical settings where gas is not distributed uniformly. Gas densities can vary over many orders of magnitude, from the low density plasma in the Intergalactic medium between galaxies, to the neutral and dense molecular regions in the interstellar medium inside of galaxies. Moreover, gas throughout space is turbulent implying it has density structure on all spatial scales.