Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

This process was first observed by Jan Ingenhousz in 1785. It corresponds to a Fokker-Planck Equation with no deterministic term and constant stochastic term, and it is generally modeled as a Wiener Process, while the Langevin formula can govern the average displacement. It is formally equivalent to the macro-scale diffusion equation with constant diffusion coefficient, and its namesake first observed it occurring for a pollen particle in water. Described by Einstein using the kinetic theory of gas, FTP name this seemingly random motion of a particle in a fluid, the namesake of a Scottish biologist.
Science