WEEK 7 - The Atmosphere

Atmosphere is mainly consisted of nitrogen (N2) and oxygen (O2) - 78% of the atmosphere´s volume is nitrogen and 21% is oxygen - and in smaller amounts we have argon (Ar), carbon dioxide (CO2), neon (Ne), helium (He), methane (CH4), krypton (Kr), hydrogen (H2), nitrous oxide (N2O), carbon monoxide (CO), xenon (Xe), ozone (O3), nitrogen dioxide (NO2), iodine (I2) and ammonia (NH3).  Carbon dioxide, methane, nitrous oxide and ozone are greenhouse gases which absorb ultraviolet solar radiation and help by keeping the Earth warm enough for life to exist.  moreover, those gases help on reducing temperature extremes between day and night. In addition, we need atmosphere´s gases for breathing  and photosynthesis. So atmosphere has a major role on life existence on Earth.

References:

• Wikipedia(2011).  Atmosphere of Earth.Retrieved on March 30, 2011 from http://en.wikipedia.org/wiki/Atmosphere_of_Earth