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.

Density values

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.

The blue liquid is denser than the yellow liquid. This is why you see them in separate layers