Water is one of the most important substances on Earth. Almost all living things need it to survive. A True Book: Earth Science series presents fascinating facts and fun activities that will engage the budding earth scientist, while exploring the fields of geology, meteorology, ecology, and more. This series includes an age appropriate (grades 3-5) introduction to curriculum-relevant subjects and a robust resource section that encourages independent study. Readers will learn how hydrologists study weather patterns and the shape of the land to predict how water will move around Earth. They will also discover how hydrologists put this knowledge to use by helping to build dams, levees, and irrigation systems.