Weight, Mass

Translation of units of mass, weight among various measurement systems.
To date, there is a huge variety of units of mass, which constitute different systems of measures.

Mass — physical quantity that determines the inertial and gravitational properties of a body in situations where its speed is much less than the speed of light.

Most mass measuring devices are based on the principle of equivalence of inertial and gravitational mass.
With the help of such devices, called scales, the mass of bodies is determined by their weight.
In spring scales, weight is measured by the degree of deformation of a flexible spring.
In lever — weight is determined by comparing the weight of the body of interest with the weight of standard (weights) of known mass.
The first samples of scales found by archaeologists date back to V millennium BC, they were used in Mesopotamia. However, in a situation of weightlessness (say, on space stations) scales are not applicable and other devices are used — massmeters, whose operation is based on measuring the period of free oscillations of a load on a spring; this period, as is known, depends on the mass of the body.