Lesson 19: Atmosphere

• Atmosphere - a mixture of gases around the Earth that surrounds it and makes it habitable
• The Earth's atmosphere is made up of different gases:

  78% Nitrogen

  21% Oxygen

  0.9% Argon

  0.1% Carbon Dioxide, other gases
• Troposphere

  • densest layer
  • temperature decreases as we go higher within this layer
  • contains air and is home to living things
• Stratosphere

  • temperature increases as we go higher
  • airplanes fly in the lower region of this layer
  • clouds rarely form in the stratosphere
• The Stratosphere contains an Ozone layer which absorbs UV rays
• Ozone layer - contains a high amount of ozone
• Mesosphere

  • temperature decreases as we go higher
• Thermosphere

  • temperature rises as we go higher
  • high energy x-rays and UV radiation from the sun are absorbed in this layer
• The Thermosphere is home to many satellites
• Ionosphere: the layer that overlaps the mesosphere and thermosphere

  • abundant in electrons and electrically charged particles called ions
• Exosphere: The outermost layer of the atmosphere, extending from 500 to 1,000 kilometers above the Earth.