Standardmassa

Standardmassa, or standard mass, is an artifact of known mass used as a reference in mass metrology to calibrate weighing instruments such as balances and scales. These masses provide a stable, traceable benchmark that enables laboratories to determine and maintain the accuracy of their measurement systems. The mass value of a standard mass is linked through a formal calibration chain to the SI kilogram, ensuring consistency across instruments, laboratories, and industries.

Historically, the kilogram was defined by the International Prototype of the Kilogram (IPK) and copies that served as primary standards. Measurements against these artifacts established the unit's realization in practice. In 2019, the SI redefined the kilogram in terms of the Planck constant, but standard masses remain essential as transfer standards. They are used to disseminate the kilogram value within measurement laboratories and to calibrate secondary standards and field instruments.

Construction and handling methods focus on stability, durability, and minimal interaction with environment. Standard masses are typically made from corrosion-resistant metals such as stainless steel or, historically, platinum–iridium alloys, and are machined to tight tolerances with precise geometry. Their masses are specified under controlled temperature and buoyancy conditions, and they undergo regular cleaning and inspection to prevent surface contamination or mass change. Storage and transport require controlled environments to preserve mass integrity, and detailed documentation accompanies each artifact, including uncertainty assessments and traceability records.

In modern metrology, standard masses continue to fulfill the role of transfer artifacts that enable accurate, reproducible mass measurements across laboratories, even as the fundamental definition of the kilogram rests on fundamental constants.