Iodine - Periodic Table of Videos
The team at periodicvideos has created a TED-Ed Lesson for every element of the periodic table. This one is about iodine, the pretty purple element, which is part of one of the professor's favorite chemical equations.
Silver iodide can be used to seed clouds, and therefore, initiate rainfall. 1 g of AgI can provide a trillion (109) seed crystals around which water vapor will condense into droplets large enough to fall to earth as rain.