Question

How does the atmospheric pressure get affected by a change in altitude?

Answer 1

Atmospheric pressure decreases as altitude increases. This happens because the Earth's gravity pulls air molecules downward, causing the air to be denser near the surface and thinner at higher altitudes. As you move higher, there are fewer air molecules above a given point, so the weight of the air column (which creates pressure) is less.

Specifically, atmospheric pressure drops by about 1 millibar for every 10 meters increase in height. At higher altitudes, the air is less dense and exerts less pressure because there are fewer molecular collisions. This decrease in pressure with altitude is significant enough to cause physiological effects like breathlessness and bleeding in the ears or nose. This is also why aircraft cabins are pressurized to maintain comfortable breathing conditions.