The atmosphere is composed primarily of nitrogen (78%) and oxygen (21%), with smaller amounts of argon, water vapor, ozone, and particulates. The atmosphere decreases in air pressure with increasing altitude. It is divided into four layers - the troposphere closest to Earth where weather occurs, the stratosphere containing most of the ozone with temperatures increasing with altitude, the coldest mesosphere where temperature decreases with altitude, and the thermosphere where temperature increases with altitude due to solar radiation.

1. Notes:
Summarize: Five lines to write on
Width ~ 3 Fingers
Key Words and
Questions:
Atmosphere Notes

2. Atmosphere
• A thin layer of gases that surround the Earth

3. What gases
make up the
atmosphere?
78% Nitrogen
21% Oxygen
0.9% Argon
0.1% Other Gases

4. What else is
in the
atmosphere?
• Water Vapor from evaporation and transpiration
• Ozone – O3, absorbs UV radiation
• Particulates – ash, dust, pollen, microscopic organisms

5. How does air
pressure
vary with
altitude?
• Air pressure is the force exerted on the surface by the
atmosphere
• Air/gases have mass
• As altitude increase air pressure decreases
• Measured using barometer

6. What are the
four layers of
the
atmosphere?
a) Troposphere
• Closest layer to Earth
• Where weather occurs
• Temperature decreases with
altitude because its heated by
reradiated heat from Earth’s surface

7. What are the
four layers of
the
atmosphere?
b) Stratosphere
• Contains almost all the ozone
• Temperature increases with altitude
due to UV Ray absorption by ozone

8. What are the
four layers of
the
atmosphere?
c) Mesosphere
• Coldest layer
• Temperature decreases with
altitude

9. What are the
four layers of
the
atmosphere?
d) Stratosphere
• As altitude increases temperature
increase due to direct solar
radiation