What is atmosphere? Besides atmosphere, what other conditions are necessary to sustain life? 

• Atmosphere - Check out Microsoft Encarta on CD-ROM to define and understand this.
• Formation & Dynamics of Earth-like Planets.  Explore the dynamics and creation of planets and relate to our on planet.

http://eis.jpl.nasa.gov/roadmap/site/slide_life.html
 
• Planetary Data System Imaging Node - images to use.

http://www.nasa.gov/gallery/photo/index.html
 
• Conditions for Life - Read "Searching for Life In Our Solar System" in Magnificent Cosmos by Scientific American (May 31, 1998).
• Ask a Scientist - about Geological Forces of our Earth and the relationship to conditions necessary to sustain life.   URL:

http://scorescience.humboldt.k12.ca.us/fast/ask/earth.htm