4 ms·
The standard metre was a rod 1 metre long, you might be thinking of the standard kilo which is a compact cylinder?
by SiempreViernes 2y ago
The standard metre was a rod 1 metre long, you might be thinking of the standard kilo which is a compact cylinder?
- fennecbutt 2y agoWas, they made the smoothest silicon sphere, Avogadro project. And now apparently they define it via physics as mentioned in ops article, "namely a specific transition frequency of the caesium-133 atom, the speed of light, and the Planck constant"