ABSTRACT
Water can come in different states such as water vapor in the atmosphere, liquid water such as sea water, springs, rivers, lakes, rain, fog, and dew, and solid water in the form of icepacks and glaciers. In order to fully appreciate what dew could bring as a new supplemental source of fresh water, this chapter provides an overview of water on earth. The cycle of water on earth represents the way water circulates between the great reservoirs of water in its three physical states liquid, solid, and vapor. Fresh water is a renewable but finite resource, which can only be renewed through the water cycle. Atmosphere contains traces of other gases and chemicals in various compositions depending on location: Nitrous oxides, sulfates from marine, volcanic or anthropic origin, and aerosols from mineral and organic dusts, sea salts, pollens, and spores from vegetation. Dew is often misleadingly viewed as a form of precipitation and confounded with fog.
