Color theory is an area of physics that can explain how the appearance of colors changes when colors are mixed, for example on a computer screen or with a printing press. Visible light can be divided into different ranges of wavelengths, which we see as different colors. The color of an object is usually the color of the light that the surface of the object is reflecting when viewed in white light. In this chapter, students will study the formation and sensation of color and investigate primary, secondary, and complementary colors. Teacher background information, assessment, safety notes, and references are provided. This book selection also includes the Table of Contents, About the Authors, An Introduction to Phenomenon-based Learning, Appendix, Credits, and Index.