The ratio of (a) the mass of a volume of material (including the mass of the water within the voids, but excluding the voids between particles) at a stated temperature to (b) the mass of an equal volume of distilled water at a stated temperature.
The ratio of (a) the mass of a volume of material (including the mass of the water within the voids, but excluding the voids between particles) at a stated temperature to (b) the mass of an equal volume of distilled water at a stated temperature.