Editing Area density (section)

===Other===

It is also an important quantity for the [[Absorption (electromagnetic radiation)|absorption of radiation]]. 

When studying bodies falling through air, area density is important because resistance depends on area, and gravitational force is dependent on mass.

[[Bone density]] is often expressed in grams per square centimeter (g·cm<sup>−2</sup>) as measured by x-ray absorptiometry, as a proxy for the actual density.

The [[body mass index]] is expressed in units of kilograms per square meter, though the area figure is nominal, being the square of the height.

The [[total electron content]] in the ionosphere is a quantity of type columnar number density.

[[Snow water equivalent]] is a quantity of type columnar mass density.