The density of a substance is simply its mass per unit volume.

Density is defined as mass divided by volume but of course how each are measured, the nature of the solid material, the units and the effects of temperature etc are all factors that affect the parameter we report. As ever Wikipedia give a start on the issue.

GeoPyccombIn one of those quirks of science, we can measure mass very accurately with an electronic balance. But volumes, especially volumes of irregular or porous materials, are harder to measure and to much less precision. The scale of the difference in resolution or precision is at least 100 fold in any standard laboratory situation. A practical work-around is to use gases instead of volumes as a displacement fluid and to measure any pressure changes and calculate volumes or volume changes. We can measure pressure and pressure changes on precision transducers to similar resolution to how we measure mass.


So to measure the volumes of solids, be they powders or machined parts or clumps or devices, we use displacement with a gas or a non wetting fluidised powder and measure pressures.

 Products Technology
 Accupyc Skeletal Pycnometer  Volume and Density paper
 GeoPyc Envelope Pycnometer  Density technology brochure
 DVVA Void analyser