Why do rainbows form?

The reflection of sunlight through individual drops of water creates a rainbow.

Rainbow is an impressive and beautiful weather phenomenon caused by the refraction of light. In order for the rainbow to form, the sun must be close to the horizon and there must be heavy fog, haze, or rain in front of the sun. An observer positioned between the sun and the rainbow would see a 180 degree arc of colors that run the visible spectrum from red to violet. In some cases, if conditions are right, double rainbows will form, with a pale rainbow in inverted colors above the main rainbow, and in other cases, a fully circular rainbow has been observed, usually from within. of an aircraft flying over the Earth.

A double rainbow can form when light refracts twice.

Although rainbows have been observed, written about, and depicted in art for centuries, their cause was not understood until physics began to explore the properties of light. Essentially, the cause of a rainbow is the reflection of sunlight through individual drops of water. Light enters the water and is reflected from the opposite side of the waterfall, reflecting off the entry point. As the angle or refraction of light changes as it is reflected, it filters the light into different colors, which arrange themselves with red at the top and violet at the bottom, because red is the longest wavelength and the shortest violet.

Someone positioned between a rainbow and the sun would see colors in the visible spectrum from red to violet.

When the double rainbow forms, the light is refracted twice, causing a fainter rainbow to be mirrored above the primary. Potentially, a triple rainbow could also form, although it is extraordinarily rare. As soon as the water dissipates enough or the sun moves, the rainbow will disappear as conditions are no longer ideal for refracting light through the drops. It is also possible for a lunar arc to form, although as humans have difficulty distinguishing colors in the dark, it often appears in shades of white and gray.

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There must be heavy fog, fog or rain in front of the sun for the rainbow to form.

People looking for rainbows should go out when the sun is close to the horizon and there is heavy rain or when there is an active storm. If the observer turns his back on the sun and looks in the direction immediately opposite the sun, he can see rainbows if conditions are right, with the apex of the arc located directly opposite the sun. In some cases, light conditions are suitable for rainbow formation in the vicinity of an observer: otherwise, the rainbow will continue to appear as if it is moving away from the pursuer until it finally disappears completely, because the observer has actually passed. by him .

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