# Weights

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Related to Weights: Weights and measures

## Weights

measures used in weighing, for graduating and checking scales, and sometimes also as measures of the force of gravity (for checking dynamometers and creating loads in mechanical tests).

Scales and weights appeared several thousand years ago, with the development of trade in ancient Mesopotamia and Egypt. Ancient Babylonian, Egyptian, Greek, and Roman weights of various shapes (particularly those of sacred animals or their heads) are known. In ancient Russia, as in a number of other countries, the monetary units (coins) functioned simultaneously as measures of weight. In Russia at the end of the 18th century, spherical cast-iron weights were established in sizes of 2 and 1 pood (1 pood = 16.38 kg), 27, 9, 3, and 1 funt (1 funt ≈ 0.41 kg), and 81, 27, 9, 3, and 1 zolotnik (1 zolotnik = 4.266 g). The use of weights with these names (but in slightly different sets) continued in Russia until the introduction of the metric system.

In the USSR and other countries using the metric system, the masses of weights are expressed in kilograms, grams, and milligrams. Weights whose masses are expressed in carats (1 metric carat = 200 mg) are often used for weighing precious stones. In the USA, Britain, Canada, and a number of other countries, both metric weights and weights whose mass is expressed in pounds, as well as fractions and multiples of the pound, are used.

A distinction is made among working weights (used for weighing; there are five classes of them), standard weights, and model weights (used for checking; there are four classes). Working weights may be either separate weights or sets of weights of various masses, or built into the scales. Built-in weights are an integral part of scales; therefore, they are used and checked only in the scales in which they are installed.

Weights are characterized by a nominal mass value, a maximum deviation from the nominal value (fit accuracy), and the limit of permissible error in the determination of mass in testing. The maximum permissible deviations (Δ) for Class 2 weights are given in Table 1 as an example.

Table 1. Nominal mass and deviations of Class 2 weights
Nominal massΔ(mg)
5 kg ...............±8.0
2 kg ...............±3.0
1 kg ...............±2.5
500 g ...............±1.6
200 g ...............±1.2
100 g ...............±0.8
50 g ...............±0.6
20 g ...............±0.4
10 g ...............±0.25
5 g ...............±0.16
2 g ...............±0.12
1 g ...............±0.08
500 mg ...............±0.06
200 mg ...............±0.04
100 mg - 1 mg ...............±0.02

The best material for accurate weights is a platinum-iridium alloy (90 percent Pt, 10 percent Ir), from which the standard kilogram is made. Accurate weights are also made of nonmagnetic stainless steel (25 percent Cr, 20 percent Ni) and nonmagnetic chromium-nickel alloy (80 percent Ni, 20 percent Cr). Aluminum and tantalum can be used for milligram weights.

Weights and sets of weights are made with nominal mass values of 20, 10, 5, 2, and 1 kg, 500, 200, 100, 50, 20, 10, 5, 2, and 1 g, and 500, 200, 100, 50, 20, 10, 5, 2, and 1 mg. Weights of large mass (from 50 to 5,000 kg, for checking automobile and railroad car scales and for dynamometers), as well as smaller masses (to 0.1 mg, for checking and calibrating torsion microbalances), are used for special purposes.

### REFERENCES

GOST 7328-65: Giri obshchego naznacheniia. Moscow, 1965.
GOST 14636-69: Poverochnaia skhema dlia gir’ i vesov. Moscow,1969.

N. A. SMIRNOVA

References in classic literature ?
Although drawn downwards by the heavy weight which hastened his rapid descent, it seemed to him as if the fall lasted for a century.
Well, now, if I take this book, and hold it out at arm's length, of course I feel its weight.
It vibrated violently under the sudden weight, but fortunately did not give way.
The marquise divined in a single glance the whole weight of the unhappiness of the superintendent.
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And thus I fought as I never had fought before, against such frightful odds that I cannot realize even now that human muscles could have withstood that awful onslaught, that terrific weight of hurtling tons of ferocious, battling flesh.
By giving the balloon these cubic dimensions, and filling it with hydrogen gas, instead of common air--the former being fourteen and a half times lighter and weighing therefore only two hundred and seventy-six pounds--a difference of three thousand seven hundred and twenty-four pounds in equilibrium is produced; and it is this difference between the weight of the gas contained in the balloon and the weight of the surrounding atmosphere that constitutes the ascensional force of the former.
The ponderous mass of rock had closed, probably for ever, for the only brain which knew its secret was crushed to powder beneath its weight.
The lateral rocks, for an instant pushed back, drew together again, and added their weight to the ponderous mass which would have been sufficient to crush ten men.
It was an oldfashioned piece of furniture, with high back and ends, and it was so heavy that even by resting the greatest weight upon the back of the Saw-Horse, the boy found himself out of breath when at last the clumsy sofa was dumped upon the roof.
Beneath the blow of a fragment of the roof, Tarzan staggered back against the door to the treasure room, his weight pushed it open and his body rolled inward upon the floor.
He grunted once or twice and shifted his weight from one foreleg to the other, at the same time moving his head from side to side and swaying the ferns.

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