knowledge/science/physics/units/Kilogram.md

1.8 KiB

obj rev
science/unit 2024-02-08

Kilogram

The kilogram (symbol: kg) is the SI base unit of mass. It is used as a fundamental measurement of mass in various fields, including physics, engineering, chemistry, and everyday life. The kilogram serves as a reference for measuring the mass of objects and substances.

History

The kilogram has a long history, with its modern definition evolving over time. The International Prototype of the Kilogram (IPK), a physical object made of platinum-iridium alloy, served as the primary standard for the kilogram since it was established in 1889. However, efforts to redefine the kilogram in terms of fundamental constants led to a new definition in 2019 based on the Planck constant.

Definition

The kilogram is currently defined as the mass of the International Prototype of the Kilogram (IPK), which is a platinum-iridium cylinder stored at the International Bureau of Weights and Measures (BIPM) in France. However, as of 2019, the kilogram is officially defined in terms of the Planck constant (h), a fundamental constant of nature, as part of the redefinition of the International System of Units (SI).

Practical Applications

  • Measurement: The kilogram is used to measure the mass of various objects and substances in laboratories, industries, and everyday life.
  • Commerce: Mass measurements are crucial in commerce for trading goods, determining quantities, and ensuring product quality and consistency.
  • Engineering: The kilogram is used in engineering for designing and manufacturing products, calculating forces and loads, and specifying material properties.
  • Healthcare: In healthcare, the kilogram is used for measuring body weight, dosage of medications, and other medical parameters.