Increases equals mass divided by volume results from a column of air pushing on an area decreases due to fewer air particles pushing down
Which phrases describe air pressure? Select three options. decreases with denser air decreases as altitude increases equals mass divided by volume results from a column of air pushing on an area decreases due to fewer air particles pushing down
The Correct Answer and Explanation is:
The three phrases that describe air pressure are:
- ✅ Decreases as altitude increases
- ✅ Results from a column of air pushing on an area
- ✅ Decreases due to fewer air particles pushing down
Explanation
Air pressure is the force exerted by the weight of air in the atmosphere on a surface. It is an essential concept in meteorology, aviation, and environmental science.
The phrase “decreases as altitude increases” accurately describes a key characteristic of air pressure. As one moves higher above sea level, the atmosphere becomes thinner, meaning there are fewer air molecules above a given area. Because air pressure is caused by the weight of the air above, less air means less pressure. This is why mountain climbers and high-altitude pilots need supplemental oxygen—the air pressure is too low to supply enough oxygen for normal breathing.
The phrase “results from a column of air pushing on an area” describes how air pressure is generated. At any point on Earth, a column of air extends from the surface all the way to the top of the atmosphere. The weight of this air pushes down on the surface below. The more massive the column of air, the greater the air pressure on the surface. This pressure is measured in units such as Pascals (Pa) or atmospheres (atm).
The phrase “decreases due to fewer air particles pushing down” gives a more detailed explanation of why pressure drops with altitude. As the number of air particles in a column decreases (due to altitude or other factors), the downward force they exert becomes less, leading to lower air pressure.
On the other hand, phrases like “decreases with denser air” and “equals mass divided by volume” are incorrect in this context. Denser air actually increases air pressure, not decreases it. And “mass divided by volume” defines density, not pressure.
Thus, the correct understanding of air pressure involves how air particles exert force, especially in relation to altitude and atmospheric weight.
