This text concerns effects of interaction light-matter which result in the colors we see, subject generally not covered appropriately in physics classes. After considerations about human visual perception, we focused in explanations to the causes of color that require the classical electromagnetism (light as an electromagnetic wave) and Drude-Lorentz model (molecular and electronic oscillators). This model subsides the understanding of scattering, reflection, refraction and diffuse light spreading phenomena. In the end of the text, for a comparison purpose and to broaden the understanding of phenomena related to color, we also discuss some causes of color which require the use of a quantum model of light.
light-matter interactions; classical electromagnetism; Drude-Lorentz model; causes of color
