How much does it cost for one rain-making?
explain in your own word" cloud seeding "
items/ chemicals used for cloud-seeding
Attempting to induce an increase in precipitation by artificial means is called rain-making. Clouds consist of minute droplets of water, but not all clouds produce rain, and when it rains, it doesn’t always pour; only a small fraction of the water droplets in each cloud reaches the ground as precipitation.
The idea that human intervention - a rain-dance, perhaps - might encourage a cloud to give up a little extra water has been around since ancient times. More recently, would-be rain-makers have attempted direct intervention, by delivering various chemicals from aero-planes in an effort to wring more rain from the clouds, a practice known as ‘cloud seeding’.
There is no possibility of rain-making in cloudless arid areas - the main condition for rain-making is to have water in the atmosphere as clouds.
For rain to fall, the water droplets in clouds must condense around small particles of solid material, until it forms drops heavy enough to fall as rain. If there are no solid particles to act as nuclei for condensation, there will be no rainfall.
Cloud-seeding supplies nuclei around which condensation can begin. This will only work for clouds where the water content is high enough for the air to be supersaturated - and the warmer the air, the more water droplets it can contain before the conditions for precipitation are reached.
The substances used to seed clouds are commonly silver iodide, common salt or dry ice (solid carbon dioxide). The substance is released into the cloud from the ground, aircraft (a more expensive method) or rockets.
So why isn’t rain-making used more often?
The main reason is that if the clouds are not there, you cannot seed them, so this cuts out most of the arid areas of the world where it would be of most use.
Another reason is that it may not work for summer rainfall. Another concern is that artificially removing water from the atmosphere in one area may reduce the precipitation elsewhere - rain-making may simply redistribute the precipitation. However, research has found that there seems to be no evidence of a decrease in precipitation downwind of rain-making projects.