3 of my favorite water cycle, rain cycle experiments. These science experiments are simple to set up and use common household items. http://lessons4littleones.com/2015/04/15/water-cycle-rain-cycle-science-experiments/
Water Cycle Craft - no instructions, but pretty easy to figure out what to do and mostly straight-cutting except for the sun which is pretty easy to make or find elsewhere. These would be fun to make for the WOW journey.