Answer:
Step-by-step explanation:
Cloud seeding is aimed mainly to stimulate rainfall.
The process consists in spraying the clouds with some chemicals, whose particles can serve as nucleation center, inducing the formation of ice. Then, liquid droplets will form around the ice particles and, when they are large and heavy enough, will precipitate.
Although this procedure has been used it is objet of study because it effectiveness is in doubt.
One of the chemicals that is mentioned in the sources for cloud seeding is silver iodide, among others.