In physics, the path of least resistance is always taken by objects moving through a system. For example, water flowing downhill follows the path of least resistance as it is pulled downward by gravity. Electricity flowing through a circuit behaves similarly; while every available path has some current flowing through it, the amount of current through each path is inversely proportional to its electrical resistance. Atmospheric disturbances (storms) flow on the path of least resistance by flowing toward zones of low barometric pressure, where lower air density offers less impedance to the storm system than higher pressure zones.
The path of least resistance is also used to describe certain human behaviors, although with much less specificity than in the strict physical sense. In these cases, resistance is often used as a metaphor for personal effort or confrontation; a person taking the path of least resistance avoids these. In library science and technical writing, information is ideally arranged for users according to the Principle of least effort, or the path of least resistance. Recursive navigation systems are an example of this.
Note: The path of least resistance applies on a local, not global, reference. For example, water always flows downhill, regardless of whether briefly flowing uphill will help it gain a lower final altitude. In physics, this phenomenon allows the formation of potential wells, where potential energy is stored because of a barrier restricting flow to a lower energy state.