Explanation:

For the uninitiated, cloud seeding or weather modification is an artificial way to induce moisture in the clouds so as to cause a rainfall. In this process, either silver iodide or dry ice is dumped onto the clouds by using an aircraft or an artillery gun which leads to a rain shower. The most common chemicals used for cloud seeding include silver iodide,potassium iodide and dry ice (solid carbon dioxide). Liquid propane, which expands into a gas, has also been used.