CHAPTER 3 THE ATMOSPHERE
LESSON 3 LAYERS OF THE ATMOSPHERE
The atmosphere is divided into 4 main layers based on temperature.
LAYERS OF THE ATMOSPHERE:
Lower layers
1. Troposphere- “tropo” means turning/changing
 Lowest layer 0-12 km (6.2 mi)
 The layer we live in
 Most dense 75% of all gases
 99% of all water vapor
 gets most of its’ heat from the Earth’s surface, the higher
you go the colder it gets
 for every kilometer you go up the temperature drops 6.5°C
2. stratosphere- means layer or spread out
 top of troposphere to 50 km
 most ozone is located here
 the higher you go up the warmer it gets because the ozone
layer absorbs heat and light from the sun
Upper layers
3. Mesosphere
 “meso” means middle 50 km to 80 km
 protects the Earth from most meteoroids
 the higher you go up the colder it gets
4. Thermosphere (thermo means hot)
 the hot ball
 starts at 80 km and continues into space
 thickest layer
 it gets hotter as you go up
 where satellites orbit
a. ionosphere
 lower portion of thermosphere
 it has the ability to boost radio signals at night
b. exosphere “exo” means outer
 the outer part of the thermosphere that goes into space
 where satellites orbit
Additional notes:
Ozone layer
 located in the stratosphere
 helps protects us from the sun’s harmful ultraviolet rays
 chlorofluorocarbons (CFC’s) which can be found in air
conditioners, refrigerators, older aerosol cans break
apart and destroy ozone
Ozone hole
 found above Antarctica
 mainly visible in late summer and early fall