From a school bench it seems to much that the wave theory of physics is boring and very tangled. But, believe, it far not so. For example, under not absolutely clear term "light dispersion" actually nothing difficult disappears.
Newton's experiments
In physics dispersion of light is called the dependence of index of refraction of substance on length of a light wave. Most its decomposition under the influence of any prism clearly demonstrates light dispersion phenomenon. The first experiments with dispersive decomposition of light were conducted by Newton. He directed a usual beam of sunlight to a prism and received what many see daily today – the prism spread out a light bunch to a set of multi-colored flowers - from red to violet. After a series of other experiments with lenses and a prism Newton drew a conclusion that the prism does not change sunlight, and only decomposes it to components. But how it turns out?
The fact is that light has a certain speed. As showed experience, the light bunch consists of a set of flowers, here their speed just and is various. That is every color a range has the speed of the movement and the wavelength. Various was also extent of refraction of color beams. Remember how the color range looks: at red color the maximum speed in the environment and the minimum extent of refraction, and at violet color which is on other end of a range, the minimum speed of light in the environment and the maximum extent of refraction.
Having conducted the experiment with a prism, Newton assumed that the difference in extent of refraction and speed of components of a light beam influences its raspadeniye. Color beams just are not in time one after another under the influence of the refracting factor and break up.
Abnormal dispersion
In physics there is also such phenomenon as abnormal dispersion. Initially Newton drew a conclusion that red light possesses the lowest extent of refraction from all flowers of a range, however later it became clear that it not always so. Other physicist – Leroux, during experiments with light refraction in various environments found out that vapors of iodine refract blue beams to a lesser extent, than red. The scientist called the open phenomenon abnormal dispersion. If at usual dispersion of light the index of refraction with increase in frequency increases, then at abnormal, on the contrary, decreases.
Where it is possible to observe dispersion
In everyday life the dispersion phenomenon, that is a raspadeniye of a light bunch on a range, it is possible to observe quite often. It is all perfectly familiar rainbow in the sky, play of light in sides of diamonds or glasses and also multi-colored sparks which morning dew on a grass scatters. Sometimes dispersion can be observed and in rainy weather – often about lamps in a damp foggy cloud it is possible to make out the real rainbow.