Sample Geology Coursework Paper on The Rainbow

The formation of the rainbow represents one amongst nature’s splendid chefs-d’oeuvres. Scientifically, the rainbow is a revelation of refraction, reflection and dispersion of light as well as proof that white light is made up of seven other colors of distinct wavelength. The rainbow is often visible early in the morning or late in the afternoon when the sun is relatively low in the sky accompanied by light showers of rainfall. To vie the rainbow one must ensure that they look away from the sun.

When a ray of light strikes a raindrop in the sky, some the light is reflected on the surface of the drop while the rest enters the drop and undergoes refraction. Since white light is a spectrum of wavelengths of distinct colors, the colors are refracted at different angles as they travel from a rare medium into a denser one. Violet is refracted the most since it has the shortest wavelength while red the least as it has the longest wavelength.

At the rear of the drop, the spectrum of colors encounters a water-air boundary and undergoes total internal reflection. As the spectrum leaves the drop, the speed of the distinct wavelengths further changes and they are refracted away from the normal as they emerge causing further dispersion. A circular band of colors if formed although an observer on the earth surface can only see an arc formed by the illuminated drops.

Sometimes it is possible to see a secondary rainbow above the primary one. This is usually formed when light from the sun strikes the raindrop at a different angle causing the spectrum inside the drop to be reflected twice before re-emerging. The secondary rainbow is often formed above the primary and the order of colors is reversed with red below and violet at the top.