Why is the rainbow always curved and the red always in the outermost layer?

The formation of rainbows is due to the refraction and reflection of sunlight in water molecules. When sunlight passes through water molecules, the light rays are refracted and reflected so that they separate into different colors, i.e., red, orange, yellow, green, blue, indigo, violet.

Since the water molecules are curved, so the path of sunlight in the water molecules is also curved. This causes different colors of light to be reflected and refracted at different angles, creating a curved rainbow on the surface of the water.

As for why red is always in the outermost layer, this is because red light has the longest wavelength and a relatively small refractive index in water molecules. Since light rays with a small refractive index are more likely to pass through the gaps between water molecules as they leave them, red rays are more likely to reach the observer's eye, thus seeing red in the outer layer of the rainbow.

Rainbow. -- It is an optical phenomenon caused by sunlight hitting water droplets in the air, which is common after rain, and has a curved shape and bright colors.

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

Halo White sunlight actually contains different colors of light, which can be roughly divided into seven colors, namely red, orange, yellow, green, blue, indigo, and violet. Under normal circumstances, we would only see the sunlight as white. But when it clears up after the rain, there are still some small water droplets left in the sky, and the white sunlight is refracted and reflected by the small water droplets.

Since different colors of light have different refractive indices, they are reflected in the water droplets in slightly different directions. If we look at the sky at a specific elevation angle, we will see different water droplets reflecting different colors of light, forming a rainbow.

Red on the outside, purple on the inside, and brightly colored ones are called'Rainbow'Also called Zhenghong.

Red on the inside, purple on the outside, and the lighter ones are called'Neon'Also called Vice Rainbow.

Neon and rainbow are both rainbow phenomena formed by sunlight being refracted and reflected by small water droplets. Light rays that are refracted twice by water droplets and reflected once are called rainbows; Light rays that are refracted twice and reflected twice by water droplets are called neon. Since neon is reflected more than the rainbow, the intensity of the light is weaker, so it is not common.

On the other hand, because the reflection path of the neon and the rainbow are different, we see that the seven colors of the neon are exactly opposite to the seven colors of the rainbow.

Purple. Inside out: red, orange, yellow, green, blue, purple. However, the actual human eye cannot see violet because it has a short wavelength and is not visible light.

Red. From the outside to the inside, it is red, orange, yellow, green, indigo, and purple. The outermost is red, and the innermost is purple.

Because red waves have the longest wavelength and the shortest frequency.