Editing Continuity equation (section)

== Probability distributions ==

If there is a quantity that moves continuously according to a stochastic (random) process, like the location of a single dissolved molecule with [[Brownian motion]], then there is a continuity equation for its [[probability distribution]]. The flux in this case is the probability per unit area per unit time that the particle passes through a surface. According to the continuity equation, the negative divergence of this flux equals the rate of change of the [[probability density]]. The continuity equation reflects the fact that the molecule is always somewhere—the integral of its probability distribution is always equal to 1—and that it moves by a continuous motion (no [[Teleportation|teleporting]]).