Density - ASTM D1505
Density is the mass of a material per unit volume.
In this method the density of a material is determined by the density-gradient technique. A material is placed in a liquid column of variable density with standard floats (glass beads of known density). The material must float between a pair of the floats. The density of the material is then calculated based on its position in the column and the densities of the glass beads.
Density Gradient Column
The formula used to calculate density is:
Density = Da + [(h - ha)(Db - Da)/(hb - ha)]
where Da and Db are the densities of floats a and b,
h is the vertical position of the material (measured from an arbitrary datum),
and ha and hb are the vertical position of floats a and b.
Density can be converted to specific gravity by dividing the density (in g/cm3) by 0.9975.