Mass properties
Lubricants - Properties and features

The density of a liquid at a given temperature is the mass per unit volume; it used to be called specific mass.

For petroleum products, it is measured at 15°C and expressed in kg/m³ or kg /dm ³ or g /cm³ .

Various methods are used to measure it:

• direct hydrometer measurement using Archimedes' principle. Immersed volume is inversely proportional to density (NF T60-101/ISO 3675/ ASTM D 1298 methods);

• pycnometer measurement, which consists of weighing a given volume into a calibrated ampoule...