Question

Draw a labelled diagram to show

1. the reddish appearance of the sun at sunrise or sunset, and
2. white appearance of the sun at noon when it is overhead.

Answer 1

(i) Reddish appearance of the sun at sunrise and sunset: At sunrise and sunset, most of the blue light and shorter wavelengths are scattered away by the particles in the atmosphere as the light from the sun near the horizon passes through thick layers of air over a larger distance. The light that reaches us is of longer wavelength (red colour), giving a reddish appearance.

(ii) White appearance of the sun at noon when it is overhead: At noon, the sun is nearly overhead. The sunlight has to pass through a much smaller portion of Earth’s atmosphere. The scattering is much less, and the Sun looks white.