Density

The density ρ of a fluid is its mass per unit volume. The densities of air and water at standard conditions of 20°C and 101.325 kPa (sea level atmospheric pressure) are
ρ_water = 998 kg/m³
ρ_air = 1.20 kg/m³

Density is a compound measure that tells us about the mass of an object in relation to its volume.

For example, if an object has a mass of 100 kg and a volume of 2.5 cubic meters then the density would be

Density = mass ÷ volume =100÷2.5=40 kg/m3.

Density Mass Volume Triangle

Units of Mass:

1 g=1000 mg
1 kg=1000 g

Units of Volume:

1 m³=1000000 cm³
1 litre=1000 ml
1 ml=1 cm³
1 litre=1000 cm³