Have you ever wondered how gravity works? This fourth grade nonfiction book, Gravity, explains how gravity affects a person's weight, space travel, and even the orbits of the planets! Students will enjoy the exciting full-color photos, illustrations, and the high-interest, informational content! Supports the development of nonfiction reading skills crucial to a young reader’s success. Includes a glossary of bold-faced vocabulary words, reading activities, an index of terms, and an answer key.