Atmospheric Layer

An atmosphere is a protective layer of gasses that surrounds a planet  The earth’s atmosphere has 5 layers  The names of the layers in order starting from the lowest layer are: troposphere, stratosphere, mesosphere, thermosphere, exosphere  All of the names have the suffix “sphere.” This is because each layer surrounds the earth  The most abundant gasses in our atmosphere are nitrogen and oxygen; most of the gasses are located in the troposphere  Some key information about each layer: o Troposphere- starts at earth’s surface and goes up about 12km; we live in this layer, and this is where weather happens (clouds, precipitation, etc); most commercial aircraft fly in this layer. The temperature and air pressure both decrease as you go higher into the troposphere o Stratosphere- starts at about 12 km and goes to about 50km high; this layer contains the ozone layer which protects us from harmful ultraviolet radiation; ultraviolet radiation is an extreme form of heat energy; it can burn you and raise earth’s temperature severely; temperature increases as you go higher into the stratosphere o Mesosphere- this is the middle layer of the atmosphere; it starts at about 50km and goes up to about 80km high; most meteors burn up in this layer, and it is the coldest layer of the atmosphere. The temperatures decrease as you go higher in this layer. o Thermosphere- this layer is named for its temperature…HOT! This is the hottest layer of the atmosphere. It is where auroras are because of the ionosphere’s charged particles. The temperature increases with height. o Exosphere- this is the outermost part of the atmosphere. Temperatures are very high but can change depending on location. This is where satellites are such as television or for cell phones; this layer blends into outer space.  Earth’s atmosphere is important because it:

  1. Provides life sustaining oxygen.
  2. Shields Earth from Sun's radiation.
  3. Provides a "blanket" that traps heat and keeps Earth warm.
  4. Provided Earth with weather which is driven by the water cycle.