Physics Paper: The Process of Formation of a Rainbow (Essay Sample)

The Process of Formation of a rainbow
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The Process of Formation of a rainbow
Renowned scholar Isaac Newton was one of the first individuals to illustrate the process of formation of a rainbow. He led to the determination of how dispersion resulted in the splitting of sunlight into different colors (Dawkins, 2010). In 2014, the National Weather Service (NWS) reported that the formation of a rainbow is still an ongoing process that requires in-depth analysis. The formation of a rainbow clearly depicts the dispersion of light as it travels through water. Sunlight consists of a range of wavelengths. The wavelengths have got distinct colors that an observer can see when viewing the sky at an angle of 42 degrees (Fowler, 2012). The study of optics exemplifies that rainbows form due to dispersion, refraction, and total internal reflection of light as it moves through water.
Rainbows have seven colors that include red, orange, yellow, green, blue, indigo, and violet (ROYGBIV). Rainbows do not only form when light passes through water but also when light travels through a prism (Buick, 2013). Both water droplets and prisms disperse light into its distinct colors. Each color of the rainbow has a distinct wavelength. Red has the longest wavelength and forms at the top of the arc while violet has the shortest wavelength and forms at the bottom of the arc (Dawkins, 2010). Rainbows mostly appear early in the morning or late in the evening. One can form a beautiful rainbow by spraying water in the direction opposite the sun (Maunder, 2011).
Refraction occurs when sunlight hits rain droplets. Some rays go through reflection back to the atmosphere while some undergo refraction into the rain droplets. The speed of light reduces at the air-water interface. This is because the rays are moving from a rarer medium (air) to water that is a denser medium (Fowler, 2012). The reduction in the speed of light causes the rays to bend, leading to refraction. After refraction, light rays go through dispersion. Sunlight has seven monochrome rays that have distinct wavelengths. During dispersion, sunlight breaks into its constituent colors. Red color undergoes the least deviation from the incident light while violet color goes through the most deviation (Maunder, 2011).
The rays undergo total internal reflection inside the rain droplets. Total internal reflection takes place when the rays travel from a medium of high density to a rarer medium such as air. In order for total internal reflection to occur, the angle of incidence has to be more than the critical angle of water (Dawkins, 2010). No reflection occurs when the critical angle is more than the angle of incidence. When total internal reflection occurs, the rays undergo reflection back to the initial air-water interface. The rays go through further refraction at the air-water boundary. The rays bend away from the normal of air and travels to the eyes of an observer (Buick, 2013).
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