Module 8 air pressure Flashcards
What is atmospheric pressure?
The force applied for a particular unit area, calculated as P = F/A.
What is the atmospheric pressure at sea level in PSI?
14.7 pounds per square inch (PSI).
What is the atmospheric pressure at sea level in metric units?
1.03 kg for every square centimeter.
At what altitude do most commercial airplanes fly?
30,000 to 40,000 feet above sea level.
What medical condition can occur at high altitudes due to thin air?
Hypoxia.
What are the symptoms of hypoxia?
- Shortness of breath
- Confusion
- Possible loss of consciousness.
Why are airplane cabins pressurized?
To mimic sea level’s atmospheric pressure of 14.7 PSI.
What physiological adjustment occurs in the ears due to altitude changes?
Ears may ‘pop’ due to pressure equalization via the Eustachian tube.
What happens to gases in the body if placed in an area of drastically lower pressure?
Gases like nitrogen would expand and form bubbles that could block vessels or destroy cells.
How does the body adapt to high altitudes over time?
By increasing the number of red blood cells to carry oxygen more efficiently.
What instrument is used to measure air pressure?
Barometer.
What is a mercury barometer?
A barometer that uses mercury in a tall tube to measure air pressure.
What is the average barometric pressure at sea level in inches of mercury?
29.92 inches Hg.
What is the average barometric pressure at sea level in millimeters of mercury?
760 mmHg.
What is an aneroid barometer?
A type of barometer that records changes in pressure on paper or a scale.
How many millibars are in one atmosphere at sea level?
1013.25 mbar.
What is the Pascal in relation to atmospheric pressure?
There are 101,325 Pa in one atmosphere.
What adjustments do meteorologists make when recording air pressure?
Adjustments for different elevations to report a standard sea-level air pressure.
What is an isoline that connects points of equal atmospheric pressure called?
Isobar.
What indicates a high-pressure center in isobars?
Isobars increase in value as they move toward the center.
What indicates a low-pressure center in isobars?
Isobars decrease in value as they move toward the center.
What factors affect air pressure?
- Temperature
- Altitude
- Water vapor.
What happens to air pressure as temperature increases at sea level?
Air pressure decreases due to the expansion of air.
What happens to air pressure as altitude increases?
Air pressure decreases.
How does humidity affect air density and pressure?
Increased water vapor decreases air density and pressure.
What is the effect of gravity on atmospheric pressure at higher altitudes?
Air expands due to decreased force of gravity.
What is the atmospheric pressure at about 18,000 feet elevation?
0.5 atmospheres of pressure.
What is the relationship between humidity and air density?
Moist air is lighter than dry air, causing lower density.
Fill in the blank: The average barometric pressure at sea level is _______.
29.92 inches Hg.
True or False: High-pressure areas typically indicate stormy weather.
False.
