These were typically viewed as inherent properties of objects.

Plato described weight as the natural tendency of objects to seek their kin.

To improve the accuracy of measurements, enhance consumer protection, foster fair competition, and facilitate economic growth and trade through technical activities that promote uniformity in national and international legal metrology laws, regulations, standards, test procedures, and enforcement.


In the 20th century, the Newtonian concepts of absolute time and space were challenged by relativity.

Einstein's principle of equivalence put all observers, moving or accelerating, on the same footing.

For example, an object with a mass of one kilogram has a weight of about 9.8 newtons on the surface of the Earth, and about one-sixth as much on the Moon.

In this sense of weight, a body can be weightless only if it is far away (in principle infinitely far away) from any other mass.

Typically, in measuring an object's weight, the object is placed on scales at rest with respect to the earth, but the definition can be extended to other states of motion.

Thus, in a state of free fall, the weight would be zero. GIOVEDI GRANDE EVENTO COL CAMPIONE ALESSANDRO GALLI!! CI SARA' DIMOSTRAZIONE PRATICA CON ALESSANDRO E ASSAGGI DEI PRODOTTI INTEGRATORI WATT! TEORICO/PRATICO SU TECNICHE DI ALLENAMENTO ED ALIMENTAZIONE!!The current situation is that a multiple set of concepts co-exist and find use in their various contexts.Discussion of the concepts of heaviness (weight) and lightness (levity) date back to the ancient Greek philosophers.Although Newtonian physics made a clear distinction between weight and mass, the term weight continued to be commonly used when people meant mass.