Density
It is often useful to know not simply the mass of an object but
rather the mass of a definite amount of the material of which it is made.
If you were to have two life-size
statues made of you, one of wax and the other of bronze, then the one of bronze would be
much heavier. A given volume of bronze is heavier than the same volume of
wax.
The mass of a unit volume of a substance is called the DENSITY of the
substance and is measured in kilogram per cubic metre (kg/m
3) or gram per cubic
centimetre (g/cm
3).
To work out the density you have to divide the
mass of an object by its volume.
Relative density
The density of a substance is often
compared with that of water and this is called the RELATIVE DENSITY of the substance.
On this scale, iron
would have a relative density of 7.87, methylated spirit 0.79 etc.
