What is a hydrometer?

The hydrometer is a scientific tool used to measure specific gravity and density of liquid based on the Archimedes principle in buoyancy. It consists of a closed glass bulb with a long thin tube attached to one end and is weighed by mercury or a lead shot under the bulb so that it can float upright. Part of the tube is marked with a scale, so when it is located in the liquid, the measured specific weight can be seen. The device is usually calibrated for use with liquid at a certain temperature and the scale on it may vary depending on its intended use. This means that the lower the density, the more the hydrometer sinks in the liquid sample. On the other hand, with a higher density, there is a greater force that lifts the bulb higher in the liquid.

In order to use a hydrometer, a liquid sample should be poured into a high glass cylinder or similar container. The hydrometer is placed vertically in a liquid with the end of the bulb, so it is bobified and float in the sample. The depth of the bulb fleet is measured by means ofThe scale on the neck of the tube and deduction should be made in the plane of the water level, not where the liquid is held alongside the neck. The scale is usually measured in terms of specific weight, with a range from just below 1 to just above it, for example 0.95 to 1.05.

Specific weight of the liquid is the ratio of liquid to the weight of the same volume of pure water. Put simply, how many times lighter or heavier is liquid than water. Because it is a weight ratio, the specific weight has no units. For example, a specific weight 1 means that the liquid has the same weight and density as the same volume of pure pipe, or if the measurement is less than 1, the liquid is less dense with a lower specific weight.

Because the density of liquid generally changes with temperature, the hydrometer is usually calibrated to be used with liquid at a certain temperature. Traditionally, the hydrometer was calibrated to measure specific weight by means of water density at 39 ° F (4 ° C) because it is a point in which pure water dIt touches maximum density. Recently, however, it is more common for one to be calibrated to 60 ° F (15.5 ° C) or 68 ° C (20 ° C). The calibration of the device will usually be marked on the neck of the tube and the liquid sample should be when measuring at a calibration temperature.

There are several different types of hydrometers that have different standards that differ depending on their use. Hydrometer for heavy liquids will usually have a scale of 1 or more and one for light liquids can have a start scale below 1. Other hydrometers include alcoholic fruit that measures in terms of alcohol evidence, and saccharometers that measure sugar density in sugar solution.