Specification of four methods for the determination of the density of plastics except cellular plastics. Method A: Immersion method for plastics in a finished condition; Method B: Pyknometer method for plastics in the form of small particles such as powders, granules pellets or flakes; Method C: Titration method for plastics in forms as required for method A including pellets; Method D: Density gradient column method, particularly suited to measurements of small samples of products and to comparison of densities.