We only notice diffraction when the opening or object is close to the size of the wavelength, so to see diffraction of light it needs to pass through a much smaller opening than a doorway. Likewise su...We only notice diffraction when the opening or object is close to the size of the wavelength, so to see diffraction of light it needs to pass through a much smaller opening than a doorway. Likewise sunsets are orange because when the sun is on the horizon the path the light travels to reach us passes through more atmosphere and even more violet/blue is removed. Notice that the plane waves on the right spread out into a circle on the left after passing through the small opening.
