The article discusses the transition from the physical kilogram prototype to a quantum-based definition of mass. The author, Jon R. Pratt, describes his experience transporting four national prototype kilogram artifacts to the Bureau International des Poids et Mesures (BIPM) in Paris for the first international pilot study of the redefined kilogram.
The new definition of the kilogram is based on fundamental constants of the universe, particularly Planck’s constant (h). This requires precise measurements using watt balances, which compare electrical and mechanical properties to determine mass. The International Prototype Kilogram (IPK) has served as the global standard for over a century, but its physical nature limits its universality and stability.
The pilot study aims to validate the new quantum-based definition of the kilogram. If successful, the redefinition will occur in 2018, marking a significant advancement in measurement science and pulling it out of the 18th century. The article also mentions a DIY watt balance built from LEGO, demonstrating the potential for public engagement with quantum-based measurement standards.
Source: https://www.nist.gov/blogs/taking-measure/world-metrology-day-kilogram-balance
Keywords: watt balance, kilogram, NIST
