Water vapor is the gas phase of water. It is formed when water reaches the boiling point, 100 °C or 212 °F at sea level. It also forms as water evaporates slowly at temperatures below boiling. It may be a component in the greenhouse effect.
- National Science Digital Library - Water Vapor (http://www.nsdl.arm.gov/Library/glossary.shtml#water_vapor)
- Measuring Water Vapor (http://avc.comm.nsdlib.org/cgi-bin/wiki_grade_interface.pl?Measuring_Water_Vapor) : A lesson plan from the National Science Digital Library.
