http://en.wikipedia.org/wiki/Cloud_seedingYour friend is not exactly insane, but they are not doing it to hurt anyone. They are doing it to keep food on your table by diverting water to areas that are in severe drought.
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Cloud seeding, a form of intentional weather modification, is the attempt to change the amount or type of precipitation that falls from clouds, by dispersing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. The usual intent is to increase precipitation (rain or snow), but hail and fog suppression are also widely practiced in airports.
This image explaining cloud seeding shows the chemical either silver iodine or dry ice being dumped onto the cloud which then becomes a rain shower. The process shown in the upper right is what is happening in the cloud and the process of condensation to the introduced chemicals.
Sources for image:
http://www.fletcherboland.com/photos/mountains/11.phpThe most common chemicals used for cloud seeding include silver iodide and dry ice (solid carbon dioxide). Liquid propane, which expands into a gas, has also been used. This can produce ice crystals at higher temperatures than silver iodide. The use of hygroscopic materials, such as salt, is becoming more popular[citation needed] after promising research.[1]
Seeding of clouds requires that they contain supercooled liquid water—that is, liquid water colder than zero degrees Celsius. Introduction of a substance such as silver iodide, which has a crystalline structure similar to that of ice, will induce freezing nucleation.
Are they dropping chemicals, yes. They are therefor chemtrails, yes.
