1. Composition of the Atmosphere

2. Vocabulary Matter Atmosphere Cellular respiration Use your book on page 252 to find the definitions

3. Atmosphere is composed of chemical elements including Nitrogen (N) Oxygen (O) Argon

4. Atmosphere is composed of chemical compounds including: Carbon Dioxide (C0 ) Water Vapor Levels of water vapor vary with evaporation and precipitation (rain, snow) Moist air may contain up to 4% water vapor Dry air may contain as little as 1% water vapor

5. The atmosphere also contains ozone Ozone is a form of oxygen consisting of three oxygen molecules Protects the earths inhabitants from harmful ultraviolet rays by absorbing them

6. Atmosphere also contains atmospheric dust which includes: Mineral particles lifted from soil by winds Ashes from fires Volcanic dust Microscopic organisms Sea spray-salt The larger particles fall due to their weight but many smaller, lighter particles remain in the atmosphere for months