The experiment that revealed the atomic world: Brownian Motion

Summary by Krater

Steve Mould explains how Albert Einstein used Brownian motion to calculate the mass of atoms and Avogadro's number, connecting microscopic particle movement to macro-scale physics equations.

From the video

Answers: How did Einstein calculate the mass of atoms using Brownian motion?

• Brownian motion
• Avogadro's number
• Diffusion coefficient
• Einstein's 1905 papers
• Molecular collisions

What it concludes

• Brownian motion occurs in both gases and liquids due to random molecular collisions.
• Einstein calculated Avogadro's number by observing the random walk of particles under a microscope and applying the diffusion coefficient equation.
• Jean Perrin calculated Avogadro's number as 7.15 x 10^23 through experiments on Brownian motion, close to the accepted value of 6.02 x 10^23.
• Einstein published three breakthrough papers in 1905 on relativity, the photoelectric effect, and Brownian motion.