Water vapor
Water vapor is water that is in the form of a vapor, or gas. It is a part of the water cycle. When liquid water is heated to boiling point, 100 degrees Celsius (212 F), it turns into vapor. Water vapor can also be produced directly from ice; this is called sublimation. Steam is water vapor, but clouds are liquid water. The amount of water vapor in air is called humidity and it affects weather conditions. In the cold, breathing out causes the water vapor in the breath to freeze.
Water vapor weighs less than air, thus slightly reduces the lift produced by an aircraft wing.
Water vapour is transparent. The small droplets that look white like mist are actually liquid.
Water vapour is a big cause of the greenhouse effect.
Water vapor is invisible but when it condenses it makes visible water.
Water Vapor Media
Fog on the St. Johns River (Florida), taken at the Shands Bridge on the Duval/St. Johns County side, 9 am
Clouds, formed by condensed water vapor
Graph of atmospheric dewpoints across a range of temperatures. It was created on August 1, 2004 based on data from the NOAA weather balloon sounding database.
Evidence for increasing amounts of stratospheric water vapor over time in Boulder, Colorado.
Some effects of global warming can either enhance (positive feedbacks such as increased water vapor concentration) or inhibit (negative feedbacks) warming. Observations and modeling studies indicate that there is a net positive feedback to Earth's current global warming.
These maps show the average amount of water vapor in a column of atmosphere in a given month.(click for more detail)
Cryogeyser erupting on Jupiter's moon Europa (artist concept)
Artist's illustration of the signatures of water in exoplanet atmospheres detectable by instruments such as the Hubble Space Telescope.
