aim: what are the major layers of the atmosphere?
TRANSCRIPT
II. Pressure Changes
- Atmospheric pressure is simply the weight of the air above.
- Measured with a barometer
- The atmosphere thins as you travel away from Earth’s surface until there are too few gas molecules to detect.
- At sea level there is 1 atm. (atmosphere) of pressure. All the air above your head creates this pressure.
Where would you expect to find the most pressure?
Where would you expect to find the least pressure?
At sea level (1 atm)
On a mountain peak
- Pressure is highest at sea level = 1.0 atm.
- As altitude increases air pressure decreases.
- At the top of the Stratosphere the pressure comes close to 0 atm.
Why does the pressure approach zero as altitude increases?
Think about what causes air pressure
- A decrease in air molecules
ESRT page 14
Sea level
1. Troposphere: (where we live!)
– 90% of all gases
– all clouds and weather
– Temp. decreases as altitude increases
What is the lowest temperature in the
Troposphere?-550C
2. Stratosphere:
– Contains Ozone Layer which blocks dangerous ultraviolet radiation.
– Temperature increases as altitude increases.What is the highest temperature in the
stratosphere?
00C
3. Mesosphere
– Meteoroids burn up due to friction with air particles forming “shooting stars”.
– Temp. decreases
as altitude increases. At what altitude does
the Mesosphere begin?
30mi or 50km
4. Thermosphere– Temperature
increases as altitude increases.
– The Ionosphereinfluences radio
communication.
- Contains “Aurora’s” or The Northern & Southern Lights