A physics course for all ages, but designed for use as young as 8th grade, First Physics is a study of physical things that emphasizes the natural rather than mathematical. Beginning with an introduction into the principles of natural philosophy, following the guide of St. Thomas Aquinas, the text goes on to cover the conventional topics of a physical science course, but properly grounded in those beginning principles. This comprehensive but easy-to-use course includes both text and key and can be used as either a one-semester or one-year course. It is based on Anthony Rizzi's ground-breaking college-level textbook Physics for Realists. * An in-depth study of the basics of natural philosophy, including substance and accidents, matter and form, change, cause and effect; * Also covers the specific principles of locomotion, including momentum as the cause of locomotion, mass, force, kinetic energy, potential energy; * Covers gravity, electricity, and magnetism; * Simple, natural explanation of measurements and graphing; * Presents a simple, natural understanding of space and time; * Builds on and develops a student's common sense; * Excerpts from original sources such as Aristotle and Aquinas are presented in the text for advanced students who desire greater depth. This radically new textbook can be used effectively by a teacher with no specialized physics background. It provides well-structured review questions at the end of each lesson. First Physics is written for high school students, mature 8th graders, and adults, at a mathematical level appropriate for those familiar only with introductory algebra.