Geography

• Composition and structure of the Earth

  • There is a thin layer of gases that surrounds the Earth, we call this layer the atmosphere
  • The amount of gases that are in the atmosphere decreases as the distance from the surface of the Earth increases
• Structure of the atmosphere

  The atmosphere consists of four different layers

  • The Thermosphere
  • The Mesosphere
  • The Stratosphere
  • The Troposphere
• #1 The Troposphere

  • The Troposphere is the layer closest to the Earth's surface
  • This layer is approximately 8km thick at the poles and 17km thick at the equator
  • This layer contains the gases which are essential to life and contains most of the air in the atmosphere
  • The behavior of the air in the air in the troposphere leads to weather
  • It becomes colder the higher you go.
• The Tropopause

  • The upper level of the troposphere is the tropopause
  • The tropopause separates the troposphere from the stratosphere
• The Stratosphere

  • This is the second layer above the Earth's surface and it lies below the Mesosphere
  • It contains a layer of ozone (O₃), ozone is a gas which absorbs ultraviolet rays from the sun
  • It becomes warmer the higher you go
• The Mesosphere

  • This is the third layer above the Earths surface and it lies below the Thermosphere
  • This layer is a cold layer
  • It prevents dust and rocks in space from entering the lower layers of the atmosphere
• The Thermosphere

  • This is the furtherest layer from the Earth
  • This layer absorbs many of the sun's harmful X-ray and ultraviolet rays
  • This is why temperature in this layer are high and rise along with an increase in the distance from Earth 🌍
• Structure of the Atmosphere

  • The factor that distinguishes one layer from the next is the change in the temperature
  • In the Troposphere, the temperature decreases as the height above the Earth's surfaces increases but, at the tropopause, the temperature starts to increase as the height above the Earth surface's increases
• Composition of the Atmosphere

  • The atmosphere is made up of solids, liquids and gases
  • These substances are vital for life on Earth
• Gases

  • The Troposphere is a mixture of gases
  • Some gases are permanent and in fixed portions, which others exist in varying amounts
  • The amount of gases in the atmosphere decreases as distance from the surface of the Earth increases
  • The further away from the Earth we go, the smaller the amount if gases in the atmosphere
• Permanent gases in the atmosphere:

  • Nitrogen (78%) this element is necessary for the growth of plants
  • Oxygen (21%) this element is necessary for respiration
  • Argon (1%)
• Gases

  • About 1% of the gases in the atmosphere are gases which exist in variable amounts, such as carbon dioxide, helium, ozone, water vapor, carbon monoxide, methane, nitrous oxide, and sulfur dioxide
  • We call some of these gases greenhouse gases because they absorb radiation, and this assist in heating the atmosphere
• Solids

  • There are also millions of minute, solid dust particles and salt crystals in the air, water vapor condenses on these
• Liquids

  • The atmosphere contains water in the form of clouds
• Why is the Atmosphere important?


  The atmosphere is essential for life

  
  

  Without the atmosphere, gases such as Oxygen, Carbon Dioxide, and water vapor which are necessary for life, would not exist

  
  

  Harmful rays from the sun would strike Earth

  
  

  Our planet will be a dessert, baked by the sun during the day and frozen at night
• The properties of the lower layer of the atmosphere allow us to experience weather conditions and climates,