What is the effect of altitude on air density?

Air density decreases with altitude due to the reduction in the weight of the air above as you ascend. At higher altitudes, there is less atmospheric pressure because there is less air pressing down from above. This lower pressure means that air is less compact, leading to a lower density. As altitude increases, the molecules of air are more spread out, which directly contributes to the diminished density.

Understanding this relationship is crucial in fields such as aviation and meteorology, where changes in air density can significantly affect aircraft performance and weather patterns. At sea level, air density is at its highest because of the weight of the entire column of air above. As one climbs to greater altitudes, the number of air molecules in a given volume decreases, resulting in lower air density.