Why does atmospheric pressure decrease as you go higher in altitude?
ABecause gravity is weaker
BBecause there is less air above you pushing down
CBecause the air moves faster at high altitude
DBecause the temperature is lower
Atmospheric pressure is caused by the weight of the air column above you. At higher altitude, there is less air above, so the weight — and therefore the pressure — is lower.
Question 2 True / False
A suction cup sticks to a wall because atmospheric pressure pushes it against the surface.
TTrue
FFalse
Answer: True
When the air is pushed out from beneath the suction cup, the atmospheric pressure on the outside is greater than the near-zero pressure underneath, pushing the cup firmly against the surface.
Question 3 Short Answer
If atmospheric pressure at sea level is about 101,325 Pa, why are we not crushed by it?
Think about your answer, then reveal below.
Model answer: Because the fluids and gases inside our bodies push outward with the same pressure. The internal and external pressures balance, so we feel no net force.
Our bodies evolved at this pressure. Internal pressure matches external atmospheric pressure, so the forces on our tissues cancel out. We only notice pressure changes, like when our ears pop during altitude changes.