What is a contrail and how does it form? Feature Summary

Physics in Your World
What is a contrail and how does it form?
The contrails in the photo above were generated by an Air Force C-141 Starlifter. Jet fuel is a mixture of hydrocarbons, which burns to produce carbon dioxide and water vapor. The water vapor condenses upon cooling to form small water droplets--the contrail--which is essentially a cloud. To  learn more, check out What is a contrail and how does it form? from the National Weather Service. Like clouds, contrails can affect global warming--to  find out how, see From Physics Research and Worth a Look.
image credit: <a href="http://www.af.mil/photos/mediagallery.asp?galleryID=2">U.S. Air Force</a>; <a href="http://www.af.mil/photos/media_search.asp?q=C-141" target="_blank">image source</a>; <a href="http://www.compadre.org/informal/images/features/strlftr-contrail-800.jpg" target="_blank">larger image<a>
image credit: U.S. Air Force; image source; larger image
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October 1, 2011 - October 15, 2011