Relaxation of Brownian particles in a gravitational field

Abstract

We describe an upper level undergraduate experiment on the time-dependent behavior of a suspension of Brownian particles under gravitational attraction. We employed the Fokker-Planck equation in the strong friction limit and measured the time-evolution of the probability distribution for 1.0μm diameter latex Brownian particles in water at room temperature and pressure. The experiment provides evidence of the atomic nature of water.