How does atmospheric pressure change with altitude?

Atmospheric pressure decreases as altitude increases due to the decreasing weight of the air above as you rise in altitude. At sea level, the atmosphere is denser, and thus the pressure is higher because of the greater mass of air exerting force downwards. As you ascend, there is less air mass above you, leading to a reduction in pressure. This principle is fundamental in aviation, as pilots need to account for lower pressure at higher altitudes, which affects aircraft performance, engine efficiency, and weather patterns. Understanding this relationship is crucial for safe flight operations and navigation through different flight levels.