How does atmospheric pressure generally change with altitude?

Atmospheric pressure generally decreases with altitude due to the diminishing weight of the air above the observer as one ascends. At sea level, the atmosphere is at its densest, and as altitude increases, fewer air molecules are present above you, which results in lower pressure. This decrease is logarithmic rather than linear, meaning that pressure drops rapidly at lower altitudes but the rate of decrease slows down at higher altitudes. Understanding this principle is crucial for pilots, as it impacts aircraft performance, weather phenomena, and altimeter settings.