See full answer below. In chemistry the commonly used units for mass are grams g and for volume are. When analyzing populations volumes dont make much sense to look at so we use area.
R m v The SI unit of density is kilogram per cubic meter kgm 3.
The density of water is about 1 kg per liter a liter of water is about 1 kg so anything that floats has a lower density and anything that sinks is more dense. Equivalently it is its mass per unit volumes. Thus Population Density Number of PeopleLand Area. Density is a derived quantity that relates a ratio of the mass of a substance to its unit volume.