After refraction → reflection → refraction, it is formed by shooting at our eyes.
The deflection angle of the rainbow beam formed by different colors of solar beams through the above process is roughly the same as that of the original beam.
180-42 = 138 degrees.
That is to say, if the sunlight is horizontal to the ground, the elevation angle of viewing the rainbow is about 42 degrees.
The following animation shows that all light beams from the same viewing angle must be on a conical surface.
(that is, a circular rainbow beam appears)
Imagine you are looking at the rainbow in the east, and the sun is setting in the west behind you. White sunlight (the combination of all colors in the rainbow) passes through the atmosphere, passes eastward over your head, and meets the water drops falling in the storm. When the light beam touches the water drop, there are two possibilities: first, the light may directly penetrate it, or more interestingly, it may touch the front edge of the water drop, bend the inside of the water drop when it enters, then reflect back from the back end of the water drop, and then leave from the front end of the water drop and refract it to us. This is the light that forms a rainbow.
The bending degree of light passing through water drops depends on the wavelength (i.e. color) of light-red light has the largest bending degree, followed by orange light and yellow light, and so on, and violet light has the smallest bending degree.
Each color has a specific bending angle. The refraction angle of red light in sunlight is 42 degrees, while that of blue light is only 40 degrees, so each color appears in a different position in the sky.
If an imaginary line is used to connect the back of the head with the sun, then the place at an angle of 42 degrees with this line is where the red color is. These different positions outline an arc. Since the angle between the blue and the imaginary line is only 40 degrees, the blue arc on the rainbow is always below the red. The rainbow is formed because sunlight enters water droplets, which are refracted and scattered. My question is.
Is the shape of the rainbow formed by water droplets (water droplets are round), that is, the rainbow is water droplets: the behavior shown; Or does the shape of the rainbow come from the shape of the sun itself and is formed by many water droplets?