Mass refers to the basic properties of matter. It exists on its own and does not depend on other parameters, such as temperature, pressure and the location of the object in space. Being a physical quantity, mass is determined by the amount of matter (substance) contained in an object, and is an internal characteristic of this body, allowing you to find other parameters that depend on it. In Newtonian mechanics, mass is responsible for gravitational attraction to other bodies and resistance to acceleration due to the force of inertia.
Who has more talents, or what were people "measured" in antiquity
All these scientific terms associated with space technology actually have their roots in ancient times. From ancient times, a reasonable person faced the question of determining the mass of various objects. Agriculture, logistics, construction, absolutely any field of activity required knowledge of weight, and over time only the requirements for accuracy changedmeasurements. Initially and still today, all mass units are based on a comparison with a selected reference sample. In the deep past, the objects of the surrounding world served as a measure, although many of them are used as a standard in our time. For example, since the 15th century, the weight of jewelry has been counted in carats (about 0.2 g) in the mass of seeds of a leguminous plant (carob tree).
In ancient Rome, the unit of mass was talent, determined by the amount of water contained in an amphora of a certain volume. Copies of weights made according to accepted reference units were reliably guarded by rulers, elders or clergymen.
Old Russian measures of weight
The first well-known measure of weight in Ancient Russia is the hryvnia, named with the same name with a precious decoration for the neck. These were silver ingots of a special form of two types: northern Novgorod, weighing 204 g, and southern (160 g) Kyiv hryvnia. A large hryvnia was obtained from a pair, it was later called a pound, which weighed about 409.5 g.
The pound was divided into smaller units - 32 lots, 96 spools, and the share was considered the smallest measure (1 spool included 96 shares weighing 0.44 grams each). To determine large masses, a pood equal to 16.38 kg and a Berkovets consisting of 10 poods were used.
How did we get to this life
With the development of interstate commodity-money relations, the need arose for a single quantitative definition of the concept of "mass". The unit of mass in the metric system (SI) was originally adopted as a gram, determined by the amount of distilled water at the melting point of ice (0 ° C) in a cubic container with sides of 0.01 m (1 cm). Later, a more convenient value for practical use was determined - 1 kilogram, corresponding to the amount of purified water in a volume of 1 dm3 at the temperature of its maximum density (in normal atmospheric pressure it is +4 °С). The prefix "kilo" is used to denote the number of measured units multiplied by 103, in the Russian version "k", the international designation "k", and it is the mass unit that is the only one of the main ones in SI, which is used with the prefix.
Because the density of water is highly dependent on atmospheric pressure, this was a very risky method of determining the unit of mass, which could cause an error in the value of the kilogram. For small values, this could lead to serious errors. Therefore, in 1889 in France, after precise measurements, the International Prototype Kilogram (kilogram) was created, which is an ingot of noble platinum (90%) and a material with a very high density - iridium (10%) in the form of a cylinder 39, 17 mm as in height, as well as in diameter. From 1878 to 1983 they created 43 copies in the image and composition of the kilogram from the archive.
The most accurate of them was taken as the international standard, which currently determines the value of the unit of mass for the member states of the Metric Convention. Hissecurely stored in the suburbs of Paris, in the commune of Sevres, and the rest were acquired by the countries parties to the agreement. Russia got two copies - No. 12, approved as a standard, and No. 26, which became the secondary standard of the kilogram. The prototype is stored in St. Petersburg, at the Institute of Metrology. D. I. Mendeleev.
Infinity is not the limit
Kilogram is great for everyday use, but becomes awkward as a unit of mass for extremely large and extremely small objects.
Let's start with the ancient Latin - centum "hundred", which defined 100 kg in the metric system in a single word - a centner, we will continue with it (Latin) - a ton (from Latin tunna "barrel") gave the name to a mass of 1000 kg. Further, it is simpler, prefixes are added to grams, centners and tons, increasing or decreasing the value of these quantities by 10 to some extent times. In the direction of increasing 10 in a positive degree: deca - in the 1st order, hecto - in the 2nd, kilo - in the 3rd, mega - has the order of 6, giga - 9, tera - 12, peta - 15, exa - 18, zeta - 21, yotta - 24.
Now let's go towards infinitesimal values. There is some compromise here, caused by the presence of the prefix kilo in the main unit, therefore, its fractional part is taken as the base value - gram: deci - 10 to the power of -1, centi - 2, milli - 3, micro - 6, nano - 9, pico - 12, Femto 15, Atto 18, Zepto 21, Iocto 24.
With the advent of molecular chemistry, it became necessary to determine the mass of atoms and molecules. For this, we enteredthe concept of an atomic mass unit (d alton), which is approximately 1.66 times 10-27kg. Due to the complexity of the calculations, the d alton was replaced by the relative atomic mass, calculated by dividing the mass of an element atom by the twelfth part of the carbon atom, this value has no dimension.
The Last of the Mohicans
Alas, but this is not all the units of mass measurement that exist in the world. In addition to metric, many countries often use historically established national systems of measures (ounce, pound, sy, tribute, livre, drachma, etc.), and three small developing countries have not yet switched to the SI system at all. These metric outcasts are Liberia, Myanmar (Burma) and… USA.
