Red glass transmits red light while blocking other colors from the spectrum, such as green and blue. When white light passes through red glass, the green and blue wavelengths are absorbed due to resonance with the glass's electrons, generating thermal energy. If red light is passed through red glass, it is transmitted without being blocked. In contrast, passing red light through green glass results in the absorption of red light, with only green light being transmitted. This discussion highlights the interaction of light with colored glass and the principles of light absorption and transmission.