Do you know what causes rainbows? Did you know that light refracts from water droplets and forms a spectrum of light in the sky? If you’ve ever seen a rainbow, you’ll know what we’re talking about – a multicoloured circular arc in the sky. Here, you’ll learn about the meteorological phenomenon that makes rainbows possible, and how to create your own. Also, read about the Intangible rules of geometry and the size of raindrops.
Primary rainbow
A primary rainbow is formed when light rays fall on raindrops at an angle of 42 degrees. These rays have many neighbors in the same direction, so each one contributes to the rainbow’s brightness. The intensity of the rainbow is dependent on the amount of light in each drop. The light rays that fall on raindrops vary in minimum deviation angles, which are explained by the color of the raindrops. Hence, a primary rainbow is brighter than a secondary rainbow.
The red, green, and blue colors in the primary rainbow change in order to form a secondary rainbow. These rays are bent through more than 180 degrees, making them appear outside the primary rainbow. Similarly, the violet and red rays are bent more than 180 degrees, making the rainbow’s outer edge appear darker. This process is called internal reflection. Originally, René Descartes explained the formation of a primary rainbow as a double rainbow, but this view was rejected by astronomers.
Inverted stripes of colours
Rainbows are arched bands of colour. The Sun’s rays travel straight up from the surface of the earth and bend and reflect in a specific way to form a rainbow. However, inverted stripes are formed because some of the light is reflected, and some is refracted. In these inverted stripes, violet is transmitted above red. The rays of the Sun are reflected at different angles by millions of prisms, and this causes them to refract in an inverted fashion.
The first rainbow flag was designed by Gilbert Baker in 1978. Its colours were chosen to celebrate the gay community and was flown in lesbian and gay pride marches around the world. In the United States, the rainbow flag gained national recognition when gay activist John Stout successfully sued a West Hollywood landlord for disallowing the display of the rainbow flag. The creator of the rainbow flag, Gilbert Baker, lives in San Francisco.
Intangible rules of geometry
While it’s true that the rainbow is unique to each person, the intangible rules of geometry make it impossible to observe the same rainbow two times. This is due to the fact that cones of colors congregate at a different point for different observers. These differences in point of convergence alter the dispersion of colors for different people. Even though rainbows are beautiful, they are a deeply personal experience.
The phenomenon is incredibly complex, and has spawned many theories. For example, the geometry of light scattering by tiny particles can explain how a rainbow is formed. However, the exact location of a rainbow is impossible to be determined with accuracy. Although the rainbow is visible, its precise location can only be determined by the angle at which it is pointing. In addition, rainbows have multiple levels of description.
Size of raindrops
The size of raindrops on a rainbow varies with the source and the amount of water in the air. Most droplets are 0.5 millimeters, although there have been instances of drops up to eight millimeters in diameter. As raindrops get larger, they break up into many smaller particles, signaling turbulence and strong updrafts. To understand the reason behind this difference, you should look for raindrops that are larger than four millimeters.
The rays of light passing through the rainbow must pass through the flattened vertical cross-section of larger raindrops. Because of this, rainbows are brighter when the raindrops are large, while a smaller raindrop will have almost no color at all. To better understand the size of raindrops on a rainbow, it’s helpful to look at real rainbows and observe how they change as raindrops get bigger or smaller.
Time of day
When is the best time to see a rainbow? A rainbow can appear at any time of day, but it is more visible in the late afternoon and later in the evening. A rainbow is more likely to appear in the late afternoon when the sun is higher in the sky. Afternoon rains are also common, but the sun is at a better angle in the west for this reason. A rainbow can be as wide as 10 degrees.
In order for a rainbow to form, the sun must be low in the sky and the rain must be falling. This rain must be falling from a cloud that is in the opposite direction to the sun. If the sun is too high in the sky, the rainbow would be projected below the horizon. If the sun is too low in the sky, the rainbow would not be visible. Alternatively, if the sun is high in the sky, a rainbow can be formed when it shines directly on the raindrops.