gen-in-3-4-sentences-explain-atmospheric-pressure-and-altitude-s-865a

In 3-4 sentences, explain atmospheric pressure and altitude. State any key formula.

Atmospheric pressure is the force exerted by the weight of air molecules in Earth's atmosphere, and it decreases with increasing altitude because there are fewer air molecules above you at higher elevations. At sea level, standard atmospheric pressure is approximately 101.3 kPa (or 1 atm), but this drops by roughly 12% for every 1000 meters of elevation gain. The barometric formula describes this relationship: **P = P₀e^(-Mgh/RT)**, where P is pressure at height h, P₀ is sea-level pressure, M is molar mass of air, g is gravitational acceleration, R is the gas constant, and T is temperature. This exponential decrease explains why mountain climbers experience difficulty breathing at high altitudes and why aircraft cabins must be pressurized.