Density is used to make a fair comparison between materials.
Density is the mass per unit volume of a material.
i.e. density is the mass of 1 cm3 or 1 m3 of a material.
The density of aluminium is 2.7 g/cm3 – this means that 1 cm3 of aluminium has a mass of 2.7 g.
All matter contains particles.
The difference between the different states of matter is how these are arranged:
Changing the temperature or the state of a material will change its density
Normally, when solids are heated their density decreases.
The spacing between the particles increases, but there is no change of mass.
So, a bigger volume has the same mass which means the density is smaller.
Similarly, when liquids evaporate the density decreases as the spacing between particles increases greatly.
The densities of some common substances
|Material||Density in grams per cubic centimetre (g/cm³)|