(Almost) any thank-you gift... just $5/month or more! GIVE NOW

The kilogram you know is so over

Nov 16, 2018
It's the final unit of measurement to stop being based on a physical standard.
NIST's platinum-iridium kilogram K92 (front) with stainless-steel kilogram masses in the background.
J.L. Lee/NIST

It’s a great day to invest in Marketplace at any level!

Donate $5/month or more today to get almost ANY thank-you gift.