whats cloud seeding and how does it work?

Answer 1

Condensation of water vapour on what is called condensation nuclei to become tiny water droplets is an important stage in the formation of clouds.Water requires a non-gaseous surface to become liquid from a vapour stage.Atmosphere usually has sufficient condensation nuclei which provide this surface for the water droplets to form when the air temperature reaches dew point.These condensation nuclei are tiny solid(dust ,salt particles, smoke etc)or liquid particles(droplets of sulphuric acid).The concept of cloud condensation nuclei has led to the idea of cloud seeding that encourages rainfall by seeding the air with condensation nuclei appropriately.
Silver iodide and dry ice (frozen carbon dioxide) are the chemicals used for cloud seeding.Salt is also added as condensation nuclei.These are injected to the clouds to produce rain.The success of this method still remains as a controversy.

Answer 2

Cloud seeding is an operation in which small particles are released into the atmosphere by plane, in the hopes that moisture will collect on the particles and rain clouds will be formed.