Gaspycnometers

A gas pycnometer is an instrument used to determine the true density of a solid or liquid sample. It operates based on Archimedes' principle, measuring the volume occupied by the sample by determining the volume of a gas displaced by it. The sample is placed in a chamber of known volume, and then an inert gas, typically helium, is introduced. The gas expands to fill the remaining volume in the chamber and also infiltrates any pores or voids within the sample. By measuring the pressure change of the gas as it expands into the sample volume, the instrument can calculate the volume of the solid material itself, excluding pore spaces. This true density is distinct from bulk density, which includes pore volume. Gas pycnometers are widely used in materials science, pharmaceuticals, and chemical industries for characterization and quality control. They are known for their accuracy and ability to measure dense and porous materials alike. The process typically involves multiple pressure cycles to ensure accurate volume measurement.