Investigation of the Effect of Density on the Speed of Light Travelling Through a Medium

摘要

The aim of this investigation is to reveal the relationship between speed of light and the density of the medium that the light is travelling through. This relationship was able to be found by directing a laser beam to a glass container bearing water, and then measuring the angle of refraction between the ray that is refracted after entering the medium and the normal axis. The speed of light travelling in vacuum(c) is a physical constant, so the change in the index of refraction of the medium would mean that the speed of light changed while travelling within the water. The basic procedure followed was to determine the refractory index of water under various values of densities, and to conclude the investigation by the data harvested during the investigation with the help of Snell’s Law and the definition of the refractory index. As the index of refraction of a substance and the speed of light travelling through it are inversely proportional quantities, a relationship between the speed of light propagating through water and its density was able to be uncovered as can be infered from the graphs. ud udThe investigation has indicated that the density of water and the speed of light travelling through it are inversely proportional quantities. Thus, this investigation was able to show that density is one of the factors that can affect the speed of light travelling in a particular environment. Although the index of refraction of a particular medium is essentially related with the temperature of the medium and the wavelength of the light directed at it, this experiment has showed that the density of the environment is also one of the variables capable of altering the speed of light.