Seven correct colors of rainbow

The seven correct colors of the rainbow are red, orange, yellow, green, blue, indigo and purple from outside to inside.

Rainbow is an optical phenomenon, which is formed by the refraction and reflection of sunlight with water droplets and ice crystals in the atmosphere after it enters the atmosphere. Rainbow usually presents arc-shaped seven-color spectrum, namely red, orange, yellow, green, blue, indigo and purple. These seven colors are due to the different refractive index and reflectivity of light with different wavelengths when sunlight passes through the atmosphere, thus forming different colors.

In our daily life, we can often see rainbows, especially after rain or foggy weather. Among the seven colors of the rainbow, red has the longest wavelength and purple has the shortest wavelength. Therefore, when arranged from the outside to the inside, the wavelengths of colors gradually become shorter, that is, the order of red, orange, yellow, green, blue, indigo and purple.

In addition to the common arc rainbow, there are different forms such as circular rainbow and double rainbow. The ring rainbow is formed because sunlight not only refracts and reflects, but also produces diffraction effect when it passes through water droplets and ice crystals in clouds. Double rainbows are formed because sunlight will be refracted and reflected many times when it passes through two or more water droplets or ice crystals.

The seven colors of the rainbow not only present a beautiful natural landscape, but also are endowed with different symbolic meanings. For example, red symbolizes enthusiasm, vitality and love; Orange symbolizes warmth, light and friendliness; Yellow symbolizes wisdom, courage and innovation; Green symbolizes life, peace and environmental protection; Blue symbolizes calmness, reason and trust; Indigo symbolizes calmness, steadiness and mystery; Purple symbolizes elegance, nobility and charm.