What is refraction?
Light can be redirected in three ways: reflection, diffraction, or refraction. Reflection occurs when light bounces off of a surface. The second method of redirection, diffraction, is the deviation from a straight path that occurs when a wave such as light or sound passes around an obstacle or through an opening. The third method, refraction, refers to the bending of light as it goes from one medium to another. Sunlight refracts when it encounters the medium of the Earth’s atmosphere, and when it goes through water. An image can look quite different after viewing it through a refracting medium.
Refraction is the bending of light or sound waves. It occurs when the wave moves from one medium to another and a change in speed is forced. Refraction creates optical phenomenon and illusions. The concept of refraction was first discovered by Willebrord van Roijen Snell in 1621. It was later modified into the formula called “Snell’s Law” by René Descartes in 1637. It is expressed as n1 sin θ1 = n2 sin θ2, where n1 and n2 are the refraction indexes of the two mediums and θ1 and θ2 are the angles between the ray and the line of the surface in the mediums. Every medium has a refraction index that tells how quickly a wave will move through it. This refraction index is found by dividing the speed of light in a vacuum by the speed of light in that particular medium. It is a ratio between the speeds of the mediums, so it is not measured in any unit. The index is always greater than one and generally increases as the density of the mediums increase. The most common example used when discussin
We see objects “breaking” at the boundary between media of different density because of refraction. Light rays are bent, or refracted, because light travels at different speeds in different media. Unless the light ray meets the boundary at exactly 90°, the direction of travel will change and the light ray is “bent.
