Density of substances

The two bodies (on the left: wood, on the right: aluminium) in the right figure each have a mass of 200 g. Nevertheless they differ widely in their size (volume).
If you cut off a piece of the wooden chunk which was as big as the aluminium piece, you would discover that the wooden chunk is much lighter than the aluminium piece.
If you compare different substances this way (i.e. iron and plastic material, ice and copper, etc.) this finding can be summarised as follows:

Bodies which are made of different kinds of material do not have the same masses while having the same volume.

The ratio between the mass of a body and its volume is called density.

whereby it applies:

• The density of solid and liquid substances also depends on their temperature.
• The density of gaseous substances depends both on their temperature and their pressure.

Some examples of the density of substances: