On Einstein's Doctoral Thesis

TL;DR

Einstein's doctoral thesis introduced a method to determine molecular dimensions, leading to an accurate calculation of Avogadro's number and laying groundwork for his later work on Brownian motion.

Contribution

The paper details Einstein's novel approach to calculating molecular sizes and Avogadro's number, highlighting its significance and practical applications.

Findings

Accurate value for Avogadro's number from solution data

Application of viscosity and diffusion theory

Foundation for Einstein's Brownian motion work

Abstract

Einstein's thesis ``A New Determination of Molecular Dimensions'' was the second of his five celebrated papers in 1905. Although it is -- thanks to its widespread practical applications -- the most quoted of his papers, it is less known than the other four. The main aim of the talk is to show what exactly Einstein did in his dissertation. As an important application of the theoretical results for the viscosity and diffusion of solutions, he got (after eliminating a calculational error) an excellent value for the Avogadro number from data for sugar dissolved in water. This was in agreement with the value he and Planck had obtained from the black-body radiation. Two weeks after he finished the `Doktorarbeit', Einstein submitted his paper on Brownian motion, in which the diffusion formula of his thesis plays a crucial role.