Avogadro's number connects these two ideas and allows us to explore atomic-level things by measuring macroscopic level quantities. It's a big deal. But why didn't Avogadro know this number?

Contrary to the beliefs of generations of chemistry students, Avogadro’s number—the number of particles in a unit known as a mole—was not discovered by Amadeo Avogadro (1776-1856). Avogadro ...

More precise estimate of Avogadro's number to help redefine kilogram Date: July 14, 2015 Source: American Institute of Physics (AIP) Summary: An ongoing international effort to redefine the ...

Theoretical Chemistry, from the Standpoint of Avogadro's Rule, and Thermodynamics. By Prof. Walter Nernst of the University of Göttingen.

Because Avogadro's number is linked to a number of other physical constants, its value can be used to express other units, such as the kilogram.