What will be the ideal response?
ANSWER: At sunrise and sunset, the rays coming directly from the Sun strike the atmosphere at a low angle. They must pass through much more atmosphere than at any other time during the day. (When the Sun is 4° above the horizon, sunlight must pass through an atmosphere more than 12 times thicker than when the Sun is directly overhead.) By the time sunlight has penetrated this large amount of air, most of the shorter waves of visible light have been scattered away by the air molecules. Just about the only waves from a setting Sun that make it on through the atmosphere on a fairly direct path are the yellow, orange, and red.
Right on time. Thanks a bunch.