Rainbow, especially when sunlight passes through water droplets, will be refracted and reflected. The refractive index of water droplets is higher than that of air, so sunlight will be refracted when it enters water droplets from air. At the same time, some sunlight will also be reflected to the surface of water droplets. Because different colors of light have different wavelengths and refractive indexes, they are refracted at different angles in water droplets, which leads us to see seven different colors, namely red, orange, yellow, green, cyan, blue and purple.
The formation of rainbow is not only related to the observer's angle, but also related to the height of the sun and the observer's position. If the observer stands on the opposite side of the sun, that is, with his back to the sun, the rainbow he sees will be a complete circle. This is because sunlight will form a complete circular halo after being refracted and reflected by water droplets, and the observer is located opposite this halo, so he can see the whole rainbow.
If an observer stands on the side of the sun, that is, the side facing the sun, the rainbow he sees will be semicircular or arcuate. This is because after the sunlight is refracted in the water droplets, only a part of the light can be reflected back to the direction of the observer, forming a semicircle or bow of the rainbow.
If the height of the sun is different, the position of the rainbow seen by the observer will also change. For example, when the sun is on the horizon, the rainbow tends to show a lower position; When the sun rises to a higher position, the rainbow assumes a higher position. This is because the height of the sun affects the angle of light refraction and the position distribution of water droplets, thus affecting the formation position of the rainbow.
Symbol of the rainbow:
1, Hope and Peace: In many cultures, the rainbow is regarded as a symbol of hope, because it represents sunshine after rain and a new beginning. After experiencing difficulties or pains, the appearance of rainbow can be regarded as a positive signal, which indicates good weather and a new beginning. Therefore, when people see the rainbow, they often feel a kind of comfort and hope.
2. Friendship and love: Rainbow is usually used to represent friendship and love. This may be because the rainbow has seven colors, representing seven different emotions: red, orange, yellow, green, green, blue and purple. In many cultures, these seven colors represent different emotions, such as red for love and courage, orange for happiness and friendship, yellow for knowledge and wisdom, green for peace and hope, blue for freedom and belief, blue for honesty and trust, and purple for elegance and nobility.
3. Healing and rebirth: In some cultures, the rainbow is regarded as a symbol of healing and rebirth. This is because the rainbow is formed by the refraction and reflection of the sun through the rain, which can purify all unclean things. Therefore, the appearance of rainbow can be regarded as a positive signal, which indicates that all bad things will pass and good things will come.
4. Protection and blessing: In some cultures, the rainbow is regarded as a symbol of protection and blessing. This is because rainbows are formed by water drops in the sky, which can protect people from wind and rain. Therefore, in some cultures, the rainbow is regarded as a protective symbol, which can protect people from danger and harm.
5. Bridge to heaven: In some cultures, rainbows are regarded as a bridge to heaven. This is because in some religions and cultures, the rainbow is regarded as a mysterious force that can lead people into another world. Therefore, in some cultures, the rainbow is regarded as a mysterious symbol that can lead people into another world.