Rainbow
Introduction
A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun.
Physical Description
Rainbows can be full circles. However, the observer normally sees only an arc formed by illuminated droplets above the ground, and centered on a line from the sun to the observer's eye. 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 when entering a droplet of water, then reflected inside on the back of the droplet and refracted again when leaving it.
Rainbow Formation
The formation of a rainbow begins when light is refracted, or bent, as it enters the surface of a raindrop. This light then reflects off the inside surface of the droplet and refracts again as it leaves the droplet and travels into the air. The overall effect is that the incoming light is reflected back over a wide range of angles, with the most intense light at an angle of 40–42°.
Rainbow Colors
The sequence of colors in a rainbow is differentiated by the varying angle at which the light is refracted, or bent, when exiting a water droplet. The light is refracted at slightly different angles for different colors of light, leading to the separation of colors. The result is a spectrum of light that, to the human eye, appears as a gradation of colors from red to violet.
Types of Rainbows
There are many different types of rainbows which can be categorized based on certain characteristics. The most common type is the primary rainbow, which has the red band on the outer part of the arch, and the violet band on the inner part of the arch. A secondary rainbow, which is fainter and has colors in the reverse order, can sometimes be seen outside the primary rainbow. Other types include the double rainbow, supernumerary rainbows, twinned rainbows, and monochrome rainbows.
Cultural Significance
Rainbows have been observed and their significance interpreted in various ways by human cultures throughout history. They often carry profound symbolic meanings, often related to gods, messengers, or supernatural events. In many cultures, a rainbow is a sign of divine favor, hope, and promise. In modern times, it has been adopted as a symbol of diversity and LGBTQ+ pride.