Which principle explains why atmospheric pressure decreases as an individual ascends in elevation?

The principle that explains why atmospheric pressure decreases with an increase in elevation is Bernoulli's principle. This principle relates to the behavior of fluids in motion and states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.

As a person ascends in elevation, the layer of air above them becomes thinner, resulting in fewer air molecules above and consequently lower atmospheric pressure. In essence, at higher altitudes, the weight of the air column above decreases, leading to a drop in pressure. This relationship is directly connected to the dynamics of fluid flow and pressure variations outlined in Bernoulli's principle.

Other principles mentioned, such as Archimedes' principle and Pascal's principle, deal with different aspects of fluid behavior. Archimedes' principle pertains to buoyancy and how objects behave when immersed in a fluid, while Pascal's principle involves the transmission of pressure in fluids at rest. The hydrostatic pressure principle specifically relates to pressure in fluids at rest and does not explain changes in pressure based on elevation like Bernoulli's principle does. Thus, Bernoulli's principle is the most relevant in understanding why atmospheric pressure decreases with altitude.