World Builders™                                                                   Session Three  --  Meteorology


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Weather is complex, arising from interactions between oceans, air, land, and solar heat.

jupiter's atmosphere
     Some planets have atmospheres. An atmosphere is composed of material that is in its gaseous state and is held to a body by gravity. There are differences of opinion about the composition of the earth's early atmosphere, but it is thought that it was composed of hydrogen, helium, nitrogen, and carbon dioxide,   with little or no free oxygen.  

    Planetary atmospheres vary in density and composition.  A small planet has less gravity than a large one, which makes it easier for gases to escape into space.  Planets close to their suns are bombarded by the solar wind, and atmospheric particles are stripped away.

     Some planets have dense atmospheres.  Venus has an atmosphere that has 90 times the pressure of the earth's atmosphere.

     On a day to day level we talk about weather, and weather happens in the atmosphere.  Different atmospheric layers have different temperatures, and temperature changes lead to winds.  Winds pick up dust and moisture and move heat about from place to place.  Water evaporates, rain falls.  The rotation of the planet affects wind and ocean movements.

     We call long term weather trends climate.  For example, on earth the climate in the arctic is different from the climate in Hawaii.  Although weather changes from day to day, the fluctuations stay within predictable ranges.  Life forms adapt to the climates that they live in. The climates that you have on your world will influence the kinds of life forms that you can have there.


Your group will work to

  • decide on the weather of your planet
  • Sketch out major air and ocean currents
  • draw maps to show the climate zones, using your relief maps
  • write a description of your planet's climate and weather.

Homework: Bring to class next session:

  • The written description of your planet's climate and weather. .
  • A diagram of major climatic ocean and air currents.
  • Your computer drawn maps of the climatic zones, now modified to show temperature and rainfall zones.

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Header from NASA Earth From Space
© 1996,1997, 1998, 1999, 2000, 2002, 2003.   Elizabeth Anne Viau. All rights reserved. This material may be used by individuals for instructional purposes but not sold. Please inform the author if you use it at .