Question

How does altitude affect air pressure and density? Check all that apply.

Air is less dense on a mountaintop than at sea level.
Air pressure is lower at low altitudes.
As you climb a mountain, air pressure increases.
More force pushes on the air at the bottom of an air column.
As you descend a mountain, air molecules are closer together.

Answer 1

Correct choices:
- Air is less dense on a mountaintop than at sea level. — True. Density decreases with altitude because the weight of the air above is lower.
- More force pushes on the air at the bottom of an air column. — True. The air below supports the weight of the air above, so pressure (force per area) is larger at the bottom.
- As you descend a mountain, air molecules are closer together. — True. Lower altitude means higher pressure and density, so molecules are more closely packed.

Incorrect choices:
- Air pressure is lower at low altitudes. — False. Pressure is higher at low altitudes.
- As you climb a mountain, air pressure increases. — False. Pressure decreases as you go up.