How does air pressure change with altitude?

How does air pressure change with altitude?

• A. Air pressure increases with altitude.
• B. Air pressure drops at higher altitudes.
• C. Air pressure stays constant with altitude.
• D. Air pressure varies randomly with no trend.

Answer: (B)

Air pressure is the force from air molecules colliding with surfaces, created by the weight of the air column above you. As you rise, there is less air above to put weight on you, and the density of air also decreases, so collisions become less frequent. That combination makes pressure fall with increasing altitude. So the correct understanding is that air pressure drops at higher altitudes.

Air pressure is the force from air molecules colliding with surfaces, created by the weight of the air column above you. As you rise, there is less air above to put weight on you, and the density of air also decreases, so collisions become less frequent. That combination makes pressure fall with increasing altitude. So the correct understanding is that air pressure drops at higher altitudes.