The atmosphere is made up of a variety of gases, but it is gases like water vapor and carbon dioxide, which make up a small fraction of the air, that have the biggest impact on us in terms of precipitation, pollutants, and global warming. The atmosphere can be described in terms of temperature and pressure.

This Reading provides background information on the underlying concepts in the Activities included in the Project Earth Science: Meteorology, Revised 2nd Edition. The Reading goes beyond what is found in the background information in the activities. The Reading can be used as supplementary information for the teacher, or to enhance classroom discussions.