Question

Why is the atmospheric pressure lower on a high mountain peak than at sea level?

A. The temperature is considerably lower.
B. The air humidity is increased at the peak.
C. The moon's force of gravity has a greater influence.
D. The air column above the peak is shorter.

Answer 1

Air has a weight, although not much. Being that high, the air "piles" up, so the bottom pressure is heavier than the air on top, similar to a pyramid being lighter the higher you go. Therefore, pressure decreases at altitude as less air is "piled up". Hope this helps.