What is Refraction?
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 discussing refraction is a straw in water. When a straw is placed in a glass of water and viewed from the side, it appears to be broken. Room temperature air has a refraction index of about 1.00027712, while room temperature water has a refraction index of about 1.33283. Since water is denser than air, the straw appears to bend as the image transmission is slowed by the density of the water.
Some other common examples of refraction are in light anomalies. Rainbows in particular are a beautiful display of refraction. Sunlight is made up of a combination of colors that appear white when they are together. When sunlight hits a substance like water or crystal, it is slowed down and angled out. Each of the colors angle slightly askew, so they are separated. The sunlight turns from white to various colors.
This seemingly mathematical and complicated process has many commonplace uses. Binoculars, periscopes, and telescopes use refraction to make objects appear closer. Fiber optic cables use refraction to transmit signals like television. Diamonds are cut in a way to use refraction to its highest level in order to create the sparkle which makes them appealing.
Written by Josie Myers
