What does pycnometer mean?
A pycnometer is a carefully calibrated container used in laboratories to measure the density or specific gravity of a liquid. Its operation depends on weighing a precisely known volume: the empty vessel is weighed, then weighed again after being filled with the sample. Dividing the sample's mass by the volume, or comparing the results with a reference liquid such as water, yields the required measurement. Pycnometers are useful when high accuracy is important or when the appearance, temperature, or conductivity of a liquid makes other methods unsuitable. They are also commonly called specific gravity bottles or density bottles. Although the basic principle is straightforward, careful cleaning, calibration, temperature control, and removal of air bubbles are essential for reliable results. The word is chiefly used in chemistry, physics, petroleum testing, and other laboratory disciplines.
nounA calibrated vessel used to determine the density or specific gravity of a liquid by measuring the mass of a precisely known volume. It is also called a specific gravity bottle or density bottle.
- A calibrated vessel, traditionally stoppered and filled with a known volume of liquid, used to determine the liquid's density or specific gravity by weighing it.
"The technician measured the density of the oil with a calibrated pycnometer."
"The apparent density of the sample was checked with a pycnometer."
"Using a pycnometer, the laboratory measured how much the purified solvent differed from water in density."
The standard plural of pycnometer.
"The laboratory has several pycnometers of different capacities."
A pycnometer finds a liquid's density by weighing a precisely known volume of it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of pycnometer
The name combines the Greek adjective pyknos, meaning “dense” or “thick,” with metron, meaning “measure.” The term thus literally refers to an instrument or vessel for measuring density. Related words such as pyknogon and pycnogon use the same Greek element pyknos in a different technical context.
Related word forms
How pycnometer is actually used
This is primarily a laboratory and technical term. Precise results depend on cleaning, calibrating, and handling the vessel properly, especially with volatile or viscous liquids.
Easily confused with pycnometer
A hydrometer determines liquid density by floating in the liquid, whereas a pycnometer determines it by weighing a known volume of the liquid.