A thematic approach provides the best opportunity for children to discover the linkage among science, mathematics, and language arts. This document explores the water cycle. Investigations are divided into six key areas: (1) comparing the size of raindrops; (2) learning to measure rain; (3) making rainbows; (4) exploring the principles of evaporation; (5) making water vapor; and (6) learning what causes thunder and lightning. After children experience the six investigations, they create their own individual water cycle book. The "Going Further" section explores different kinds of rain and how rain can affect the earth. Topics include drought, floods, and erosion. The foundation of each lesson is a shared science experience. Using the scientific method, children are given opportunities to hypothesize, investigate, and discover principles about rain by recording their predictions and findings in individual science journals. Also included are reproducible student worksheets and poetry on the subjects. Contains 42 references. (MKR)