What is a RAINBOW and how is it formed

One of the Meteorological phenomena What surprise us the most when we see them is the appearance in the sky of a rainbow and it draws our attention precisely because of its beauty, because of the relative infrequency with which they appear and, above all, because we hardly know the reasons why form. Therefore, in this lesson from a TEACHER we will talk about what is a bowíris and how it is formed. If you want to know more about this curious phenomenon, keep reading to find out more!

Index

1. What is a rainbow: explanation for children
2. How rainbows are formed
3. Rainbow classes
4. Myths and legends about rainbows

A rainbow (or rainbow) is an optical phenomenon that appears when certain weather conditions occur. The water that is dispersed through the atmosphere gives rise to a reflection or refraction of the rays of light from the sun, which end up forming an arc made up of stripes of different colors that we know as rainbows (logically, this arc does not exist physically, only we see).

When sunlight shines through the water droplets, it decomposes into these colors that we see, that is why rainbows usually appear when it rains and immediately (or simultaneously) the sunlight that filters through the clouds appears.

This sunlight breaks down forming the arc consisting of a red line towards its external part and a violet line towards its internal area, and in the middle it turns towards other colors. These shades, although of different intensity, are normally seven: violet, blue, cyan, green, yellow, orange and red. Sometimes a double rainbow can form, as we will see later.

Rainbows are formed when sunlight passes through droplets of water suspended in the atmosphere, as we previously commented. When this light passes through the atmosphere and the drops, it is divided between two spaces that have different densities (the air and the water drop), so that the light ray modifies its path angle (it is refract).

Subsequently, is reflected on one of the internal faces of the water drop and, when it comes out again, it refracts again.

The rainbow usually appears after a rain or where it exists humidity in the air, as in the vicinity of the splashing of a river or by the dew of the sea and the observer has to be looking at the drops of water and with the sun behind to see it.

Most people believe that they have seen everything there is to see in terms of rainbows, which is the simple rainbow image. However, depending on the atmospheric conditions we can see a different projection of the luminous arc. Between the types of rainbows that we can observe are the following.

Primary rainbow

Sometimes known as a simple rainbow, it is the best known of all rainbows and the one that everyone has in mind. This type of rainbow is formed after a storm or in places of splashing water, such as a cataract, since they are observed when sunlight passes through a drop of water. The intensity that is observed in the seven colors of the arc depends on the thickness of the drop of water that the light passes through.

Secondary rainbow

This type of rainbow is also called a double rainbow, and if you've seen a primary rainbow, chances are that you have also seen a secondary one, as they are formed behind these when the water drop is reflected twice instead of one.

The secondary rainbow is twice as wide as the primary one, but its colors are much less intense and are usually inverted with respect to the primary one.

Alexander's dark band

The so-called dark band of Alexander is not a rainbow itself, but it is classified as a type of rainbow because it is associated with the presence of primary and secondary rainbows. This band represents the area of ​​the sky that lies between the primary and secondary rainbows and is slightly darker than the rest of the sky.

The reason for this darker sky band is that the reflected light from the primary rainbow illuminates the inner sky and the secondary light illuminates the outer sky. The result is that a darker area of ​​sky appears between the two rainbows before our eyes.

Supernumerary rainbows

These types of rainbows do not appear very often and appear as several fainter rainbows located in the innermost part of the primary or sometimes around the secondary.

They are formed because light is reflected in smaller droplets and light that travels a different path, but inside the same droplet.

Red rainbow

Red rainbows, also called monochromatic rainbows, form right after the rains or during sunrise or sunset, when the sun is situated at or near the horizon. In these rainbows, the shorter lengths of the spectrum of light, such as blue or green, are scattered between the dust and air molecules and remain hidden in the arc of light, revealing only the colors with the longest wavelengths, such as yellow or red, but ultimately only a red arc is formed.

Rainbow of clouds

These rainbows instead of forming from drops of rain, are formed from the drops of water that occur in the clouds and in humid air. These rainbows appear white, since the water droplets in the clouds are smaller than those in the rain and cannot reflect the entire spectrum of light.

Cloud rainbows are wider than normal rainbows and it is much more common to see them formed over water. Although they are not common, they can form on the ground only when the fog is thin enough that it can be penetrated by sunlight.

Twin rainbows

Although they are often confused with double rainbows, they are not the same. It is a very rare type of rainbow and is formed when two arches are born from the same point. The conditions for them to arise occur when large and small drops fall from the sky and large drops are flatten by air resistance, while small hold their shape by tension superficial.

Reflected and reflective rainbows

These rainbows form on water (and they are not the same). Reflected rainbows are more common and arise when light is deflected from water droplets and subsequently reflected off the water, before we perceive it. with the eye, while the reflector appears before the light is deflected in the water droplets and at the moment that the light is reflected on the surface of the Water.

Rainbow wheels

These are formed when the dense clouds or the rains prevent us from seeing the light and the raindrops do not allow us to see the arch, thus that what we perceive is something similar to a car wheel, consisting of several central spokes directed towards a point. If the clouds are moving across the sky, it seems that the wheel is moving.

Lunar rainbow

These rainbows are seen at night due to moonlight. Since the moonlight is very weak, this type of rainbow is very rare to see. The best time to see them are on full moon nights with very dark skies, when these rainbows can be very opaque or white.

Although there is a scientific explanation for this phenomenon, throughout history there have been various myths and legends about the appearance of rainbows. For example, biblical tradition suggested that rainbows were a creation of God to a promise made to Noah that a universal flood would never again break out.

There are also myths about the formation of rainbows. One of them, known as the myth of the seven butterflies, He tells us that several centuries ago seven butterflies lived in the heart of a dense jungle, each one of a tonality, representing the seven colors that make up the rainbow. These butterflies were admired by the villagers for the striking effect they produced between the plants when they took flight.

In this way the days passed, until one night one of them was seriously injured with a thorn. Then, the other butterflies came to his aid, very concerned, but they soon realized that the damage was irreversible and that nothing could be done to save his life.

However, the other six butterflies could not bear the idea of ​​saying goodbye to their friend, so they begged to remain by her side forever, until, Suddenly, a strange voice arose from the sky and asked if they were willing to part with their own life to remain eternally with their friend. Without thinking for a second, the six butterflies answered affirmatively. Then the sky was covered by very thick black clouds and a sudden storm fell on the jungle. In the middle of the storm and the strong blizzard, a tornado arose that engulfed the seven butterflies and lifted them into the sky, until sails from the ground were no longer possible.

Once the storm and the wind ceased, the sky cleared and the sunlight broke through in him with great intensity. Then the inhabitants of the town caught a glimpse of a beautiful arch that illuminated the entire sky and showed with great beauty each of the seven colors of the seven butterflies. In this way, the rainbow emerged as a symbol of friendship between seven butterflies who decided to stay together until the end of their days.

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