Question

Why does air pressure decrease the higher you get in altitude?

Answer 1

Air becomes less dense with increase in altitude,less air particles contribute to the pressure at high altitude, the atmospheric pressure is caused by the continuous collision of air particles. Air pressure is also affected by the depth of the atmosphere.

Complete Step By Step Answer:
Air just like water consists of particles which are in motion continuously they bump into each other and exerts pressure.
The graph between pressure and altitude is an exponentially decreasing graph so we can conclude that with increase in altitude there is decrease in air pressure.
The reasons behind this are as follows:
As we climb higher in altitude, there is less air.
The density of the air decreases as the weight of the air decreases.
Because the amount of air particles is reduced, the number of collisions is reduced.
The air pressure above the surface is affected by the density and depth of the atmosphere. Because most air particles are drawn closer to the earth's surface by gravity, air particles near the surface are dense. There will be more collisions as the number of particles increases, resulting in increased pressure.
At sea level, the depth of the atmosphere (the distance from top to bottom) is highest, and it diminishes as one ascends higher in altitude. More air is pressed down from above as the depth of the atmosphere increases. As a result, air pressure is highest at sea level and decreases as altitude rises. The air pressure at the summit of Mount Everest, the world's tallest mountain, is only around one-third that at sea level.

Note:
Atmospheric pressure is also known as barometric pressure. Barometer is used to measure the atmospheric pressure
Formula for finding atmospheric pressure ${P_h} = {P_0}{e^{\dfrac{{ - mgh}}{{kT}}}}$
Where, ${P_h}$ = pressure at height h
${P_0}$ = sea level pressure
$g$ = acceleration due to gravity
$k$ = boltzmann’s constant
$T$ = absolute temperature
$m$ = mass of one air molecule.