Exploring Brownian Motion with a Millikan Oil Drop Apparatus

Historically, Brownian motion provided strong support for the atomic nature of matter.^1–3 In 2021, German oceanographer Hasselmann was awarded the Nobel Prize in Physics for his contributions to climate evolution modeling. In analogy with Brownian motion, Hasselmann built the stochastic climate model and explained long-term climate variability caused by the short-term fluctuations of the atmosphere.³ Hasselmann’s stochastic climate model shows the application of Brownian motion theory in complex systems. In pedagogy, demonstrations and measurements of Brownian motion have been widely reported,^4–9 for example, demonstrating a random walk^4–7 and measuring Avogadro’s^6–8 and Boltzmann’s⁹ constants. Recently, video recording and analysis^4–7,9 made quantitative analysis of Brownian motion more convenient. In this paper, we study Brownian motion with a Millikan oil drop apparatus. We were motivated to develop this education module by errors on the oil drop experiment from Brownian motion. The goals of this work are...