What is density?
The density of an object or substance is its mass divided by its volume: Density = Mass ÷ Volume.
The units of density depend on the units used for mass and volume, but are usually: g/cm³ (if mass is measured in g and volume in cm³).
The more dense a substance is, the heavier it feels for its size.
The densities of some everyday substances are:
Steel has a density of 7.82 g/cm³
Water has a density of 1.00 g/cm³
Air has a density of 0.0013 g/cm³
These values show that the steel (solid) is the most dense while the air (gas) is the least dense.