There are 3 main types of cloud seeding substances used for Royal Rainmaking Operation. i.e. endothermic, exothermic and cloud condensation nuclei substances. The principle of seeding materials selection is the consideration of its properties and daily atmospheric conditions.
Endothermic seeding materials is the seeding materials that reduces surrounding temperature by absorbing heat form the surrounding to activate or enhance the formation and growth of cloud droplets. Urea is one kind of endothermic seeding materials that used in rainmaking operation.
Exothermic seeding materials is the seeding materials that enhances the environment temperature by releasing heat to the surrounding, thus the atmospheric temperatures or cloud temperatures go up. At present, there are 2 types of exothermic seeding materials i.e. calcium chloride and calcium oxide used in rainmaking operation.
Cloud condensation nuclei or CCN provides the surface for water vapor molecules to condense into liquid form. At present, Sodium Chloride (formula 1) is used as CCN substance for rainmaking operation.