Metrology and Standards - Mark Keller, U. S. National Institute of Standards and Technology from sesame street d Watch Video

⏲ Duration: 14 min 49 sec
✓ Published: 09-Feb-2015

Description:
Redefining the International System of Units for the 21st CenturynMark Keller, U. S. National Institute of Standards and TechnologynnThe SI (from the French Systeme International d'Unites) grew out of the metric system established in France in 1799. It was formalized as an international treaty in 1875 and given its current name and structure in 1960.With the notable exceptions of the second and the meter, now linked through a fixed value of the speed of light in vacuum, the SI has remained remar