Rainbow, also known as rainbow, is an optical phenomenon in meteorology. When the sun shines on the water droplets in the air, the light is refracted and reflected, forming an arched color spectrum in the sky, which is a common phenomenon after rain. Curved, usually semicircular. Rich and colorful. The most common sayings about seven-color light in East Asia and China (in descending order of wavelength) are red, orange, yellow, green, blue, indigo and purple.
Observation of Rainbow Phenomenon in Ancient China;
As early as the Tang Dynasty in China, Sun Yanxian (Sun Sigong), a scholar proficient in astronomical calendar calculation, put forward that "the rainbow is the shadow of China and Japan, and both sunshine and rain are there." Some people explain that the rainbow is the refraction and reflection of the sun light by water droplets.
Sun Yanxian's discovery was later quoted and confirmed by Shen Kuo's Meng Qian Bi Tan in the Song Dynasty. Shen Kuo also observed that the position and direction of the rainbow and the sun are relative. Sun Yanxian, Shen Kuo and others discovered rainbows hundreds of years earlier than the West.
Western observation of rainbows;
1307 In Europe, it was suggested that rainbows were caused by the refraction and reflection of sunlight by water droplets.
Descartes found in 1637 that the size of water droplets does not affect the refraction of light. He experimented by injecting water into the glass ball and got the refractive index of water to light. He mathematically proved that the main rainbow is caused by reflection at the water point, while the auxiliary rainbow is caused by two reflections. He calculated the angle of the rainbow accurately, but failed to explain its colorful colors.
Later, after Newton used a glass prism to scatter sunlight into colors, all the optical principles about the formation of rainbows were discovered.
Myths and legends
Rainbow occupies a place in myth because of its beautiful and mysterious phenomena. Only after Galileo's monograph on the characteristics of light appeared can people explain the rainbow phenomenon. In China mythology, Nu Wa tried to make up the sky with five-color stones, and the rainbow was the colored light emitted by the five-color stones. In China, the rainbow can be regarded as a two-headed snake/dragon, while Bai Hong's crossing the sky is regarded as an ominous sign. Among Taroko people in Taiwan Province Province, the end of the rainbow is the location of the ancestral soul.
In western and Greek mythology, the rainbow (Iris) is the messenger of communication between heaven and earth; In Irish folklore, goblins put treasures at the end of the rainbow; In Indian mythology, the rainbow is the bow of Indra, named Indra Hanush. ; In Norse mythology, the Rainbow Bridge (Bifr? St) Connect the realm of God "Asgard”(Asg? Rd) and the human settlement "Middle Earth" (Midg? rd).