Atticus shows this in the smallest of ways, such as with the family's ornery old neighbor, Mrs. Dubose, who makes a habit of taunting Jem and Scout when they walk by her house. Just hold your head high and be a gentleman, Atticus advises Jem.
As light continues to move though the atmosphere, yellow wavelengths are scattered leaving orange wavelengths. Further scattering of orange wavelengths leaves red as the predominate color of sunlight. Therefore, near sunrise and sunset, a cloud's color is what sunlight color it receives after Rayleigh scattering.
Blue light from the sun is scattered every which way, much more so than the other colors, so when you look up at the daytime sky you see blue no matter where you look. This scattering is called 'Rayleigh scattering'; the amount of scattering goes as the frequency of the light to the 4th power.