HOW RAINBOW HAPPEN

Dessy Nur I
A rainbow is an optical and meteorological phenomenon that causes a spectrum of light to appear in the sky when the Sun shines on to droplets of moisture in the Earth's atmosphere. It takes the form of a multicolouredarc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun.
In a "primary rainbow", the arc shows red on the outer part, and violet on the inner side. This rainbow is caused by light being refracted while entering a droplet of water, then reflected inside on the back of the droplet and refracted again when leaving it.
In a double rainbow, a second arc is seen outside the primary arc, and has the order of its colours reversed, red facing toward the other one, in both rainbows. This second rainbow is caused by light reflecting twice inside water droplets. The region between a double rainbow is dark, and is known as "Alexander's band" or "Alexander's dark band".
The rainbow is not located at a specific distance, but comes from any water droplets viewed from a certain angle relative to the Sun's rays. Thus, a rainbow is not a physical object, and cannot be physically approached. Rainbows can be caused by many forms of airborne water. These include not only rain, but also mist, spray, and airborne dew.