What Is Gravity?

This stimulating and accessible volume offers readers a fascinating view of a force known as gravity. Readers examine many scientific concepts, including Newton's laws of gravity, mass and gravitational forces, galaxies, satellites, Earth's solar system, centrifugal force, tides, and erosion. Vocabulary boxes provide additional guidance to readers, and the "Compare and Contrast" and "Think About It" sidebars give students opportunities to ponder concepts in fun and creative ways; for example, "Earth has more mass than Mars. If you stepped on a scale on Mars, would you weigh more or less than you do on Earth? Why?"