3 ms·

Fun fact: while mainly dealing with insane precision machines, NIST have also designed a LEGO watt balance that you can use to determine mass based on the new S

• Animats 10y ago
  That's very neat. It relies on the accuracy of the electrical current measurements, though; it's not an absolute measurement from fundamental physics. For that, NIST has a fundamental standard for the standard volt.[1] So the fundamental standards now are time (atomic clock), the speed of light in vacuum, and the standard volt. The meter is now defined in terms of the speed of light in vacuum and a time. [1] https://www.nist.gov/news-events/news/2013/04/primary-voltage-standard-whole-world https://www.nist.gov/news-events/news/2013/04/primary-voltag...