The term refraction simply refers to the bending of waves because of the variations in speed when these waves pass from one medium into another. Although people usually associate this phenomenon with light, it can also be linked with sound. Refraction occurs when waves travel from one medium to another at a particular angle, and one side undergoes a variation in speed before the other side, which then results in it turning towards the slower side. In the context of light, refraction can lead to objects appearing displaced, while in relation to sound, this phenomenon can amplify sounds that are distant.
Since the time of the ancient Greeks, refraction has been recognized and there are various people who throughout history who tried to create laws that can depict this phenomenon. One example is Willebrord van Roijen Snell, who is a Dutch astronomer that formulated a mathematical law about refraction in 1621. This mathematical formula was revised in 1637 by RenÃ© Descartes and was given the name Snell’s Law. This law is commonly used to compute the refraction angle of light that travels from one medium to another.
One of the most common examples of this phenomenon is the occurrence of rainbows, which form when the raindrops refract the sunlight. Because sunlight is a combination of different wavelengths of light, the shorter wavelengths are bent more compared to the longer wavelengths, when the sunlight travels through the raindrops. When this happens, the sunlight also becomes fragmented into different colors.
Probably some of the most prevalent applications of refraction are in prisms, which are used to separate light into its various colors in order to examine the source of the light; as well as the lenses, which are devised in such a way that the light that enters is focused towards a certain point through refraction. When the light that enters the lens gets refracted, the object will appear magnified such as in telescopes and binoculars.