How are valleys made? Where does rain come from? What is a glacier? Readers will learn the answers to these questions and more in this basic geology series. Engaging, easy-to-read text explains how the earth's surface changes over time. Scientific concepts including gravity as well as the three states of water are explained in relation to real-life geology. Colorful, oversized photos and labeled diagrams aid comprehension. Facts, a glossary with phonetic spellings, and an index are also included. This series will leave readers with a deeper understanding of planet Earth and its natural wonders.