Myra Calvani's book, The Water Cycle, is a good one to use for teaching science to young children.
The information is presented in an amusing way so even little kids can understand it, while the educational activities at the end will be helpful for teachers and homeschooling parents.
Unlike most books on this topic, Calvani mentions some of the negative things about the water cycle such as the possibility of floods and being painfully hit by hail. Children need to be aware of things like that.
The illustrations by Alexander Morris communicate a lot through the expressions of people and animals and his personalized depictions of the raindrops, clouds, and other aspects of the water cycle are cute and amusing.
This book is the first in the Waterplay Series and I expect future books in the series to be equally as informative and amusing.