hydrometersHydrometers (densitometer) - devices for measurement of density of liquids (Fig). The lower, the extended part of the hydrometer filled with shot or a special mass. In the narrow upper part of the scale is calibrated in terms of density (g/cm3) at temperature indicated on the hydrometer (usually 20 degrees). At this temperature, and should be made density.
Some hydrometers equipped with a thermometer. The investigated liquid is poured into the glass cylinder and is immersed in it with a clean dry aerometer (he must swim in the liquid, not touching the walls of the cylinder). The reference density to produce transparent liquid on the bottom, and for opaque at the top of the liquid meniscus. Thermometers, scales which graduated in bulk or weight percentage, determine the concentration of solutions (spirometry, ChromaTRU and others), density of milk (lacto-density-meter), density of urine - aromer (see).

Hydrometers (from the Greek. araios - friable, liquid and metreo - measure) - devices for measurement of density or specific gravity of liquids. Sealed glass tube (Fig.), at the bottom, expanded, part of which is cargo (mercury, lead shot), and at the top, narrow part of the graduated scale.
Hydrometers graduate so that at a certain temperature (usually 20 degrees) division of the scale, which is submerged floating in the liquid A., answered the density of the liquid. Depth A. depends on the density of a liquid: the less the density, the deeper it sinks. A. special purpose (ChromaTRU, spirometry) graduate in units of concentration of this substance. Along with separate areometers a specific series, in which each A. designed for measurement in a narrow range of densities. A set of eurometro (see) consists of two A. limits of measurement 1,000 - 1,025 and 1,025 - 1,050 g/cm3.
When determining the density in the cylinder pour the investigated liquid and is immersed in it dry A. so that he did not touch the walls of the cylinder. The reference density scale in transparent liquids produced on the bottom, in muddy - on the upper edge of the meniscus.

Hydrometers with graduation ratio: 1 - with a thermometer; 2 - without thermometer.