Twaddell scale, formerly used in the bleaching and dyeing industries.Oechsle scale, used for measuring the density of grape must.Brix scale, primarily used in fruit juice, wine making and the sugar industry.Baumé scale, formerly used in industrial chemistry and pharmacology.API gravity, universally used worldwide by the petroleum industry.Modern hydrometers usually measure specific gravity but different scales were (and sometimes still are) used in certain industries. In many industries a set of hydrometers is used - covering specific gravity ranges of 1.0–0.95, 0.95–0.9 etc. In fact, it is usual to have two separate instruments, one for heavy liquids, on which the mark 1.000 for water is near the top of the stem, and one for light liquids, on which the mark 1.000 is near the bottom. In low-density liquids such as kerosene, gasoline, and alcohol, the hydrometer will sink deeper, and in high-density liquids such as brine, milk, and acids it will not sink so far. It later appeared again in the work of Jacques Alexandre César Charles in the 18th century. Īccording to the Encyclopedia of the History of Arabic Science, it was used by Abū Rayhān al-Bīrūnī in the 11th century and described by Al-Khazini in the 12th century. You can then count the notches at your ease, and in this way ascertain the weight of the water. Whenever you place the tube in water, it remains erect. The cone and the tube have one base only. A cone forms a lid at one of the extremities, closely fitted to the tube. It has notches in a perpendicular line, by means of which we are able to test the weight of the waters. The instrument in question is a cylindrical tube, which has the shape of a flute and is about the same size. Hypatia is given credit for inventing the hydrometer (or hydroscope) sometime in the late 4th century or early 5th century. In Synesius' fifteenth letter, he requests Hypatia to make a hydrometer for him. (See also Relative density and hydrometers.) HistoryĪn early description of a hydrometer appears in a letter from Synesius of Cyrene to the Greek scholar Hypatia of Alexandria. Thus, the lower the density of the substance, the farther the hydrometer will sink. Operation of the hydrometer is based on Archimedes' principle that a solid suspended in a fluid will be buoyed up by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid. Hydrometers may be calibrated for different uses, such as a lactometer for measuring the density (creaminess) of milk, a saccharometer for measuring the density of sugar in a liquid, or an alcoholometer for measuring higher levels of alcohol in spirits. A variety of scales exist, and are used depending on the context. Hydrometers usually contain a scale inside the stem, so that the specific gravity can be read directly. The point at which the surface of the liquid touches the stem of the hydrometer is noted. The liquid to be tested is poured into a tall container, often a graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely. The lower the density of the fluid, the deeper the weighted float B will sink the depth can be read off the scale A.Ī hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids that is, the ratio of the density of the liquid to the density of water.Ī hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |