Brownian motion diverges as the window shrinks, thus rendering the calculation a singular perturbation problem. Brownian motion Brownian motion or pedesis (from "leaping") is the random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the fast-moving molecules in the fluid. This pattern of motion typically alternates random fluctuations in a particle's position inside a fluid sub-domain with a relocation to another sub-domain. Each relocation is followed by more fluctuations within the new closed volume. This pattern describes a fluid at thermal equilibrium, defined by a given temperature. Within such fluid there exists no
Brownian motion model to describe a particle undergoing Brownian motion. The model assumes collisions with "M" ≫ "m" where "M" is the test particle's mass and "m" the mass of one of the individual particles composing the fluid. It is assumed that the particle collisions are confined to one dimension and that it is equally probable for the test particle to be hit from the left as from the right. It is also assumed that every collision always imparts the same magnitude of Δ"V". If "N" is the number of collisions from the right and "N" the number of collisions from the