Science

• Atmosphere


  Bracket of air that surrounds planet earth
• Air


  Mixture of several colorless odorless and tasteless gases held by the earth's gravity
• Nitrogen


  • Most abundant gas in the atmosphere
  • Important component of protein
• Oxygen


  • Second most abundant gas in the atmosphere
• Carbon dioxide


  • Comprises a tiny fraction of the atmospheric gases
• Troposphere


  Layer nearest to earth's surface
• Tropopause


  Upper boundary of the troposphere
• Stratosphere


  Layer immediately above the troposphere
• Stratopause


  Upper boundary of the stratosphere
• Mesosphere


  • Starts just above the stratosphere and extends to a height of about 85 km above sea level
  • The gases in this layer are in an excited state as they absorb the heat from the sun
• Mesopause


  Separates the mesosphere from the next layer of the atmosphere
• Thermosphere


  • Starts just above the mesosphere and extends to about 600 km above sea level
  • This layer contains a tiny fraction of the atmospheric gases
• Ionosphere


  About 258 km thick and reach in charge particles or ions
• Ozone layer


  • Found within the troposphere
  • An unstable bluish gas composed of three atoms of oxygen
• Greenhouse effect


  The natural warming of earth attributable to the presence of atmospheric gases
• Freon


  A synthetic chemical substance that contains chlorine and bromine
• Pollution


  Undesirable change in the physical chemical and biological conditions of the environment
• Global warming


  Phenomenon of increasing average air temperature near the earth surface for nearly 2 centuries