The process of rainbow

THE PROCESS OF RAINBOW

First of all,  white light from the Sun has to hit the raindrops at a certain angle before a rainbow is possible. It is best if the sun is fairly low in the sky such as dawn and late afternoon. The angle is important as it effect the direct the light travels after it hits the raindrops and that determines whether or not we will see a rainbow. Then, it is possible to see through a glass window but, at the same time, see your own reflection. Water can do this too. When light from the sun hits a water droplet, some of the light is reflected. This light will obey the law of reflection. Next, the light that is not refracted crosses the air-water interface. When this happens it slows down because the water is more dense than the air. After that, white light is made up of a spectrum of colours, each with its own wavelength. Different wavelengths travel at different speeds and when they encounter a change to medium that is more dense or less dense, the speeds are efected by different amounts.   Moreover, at the rear of the raindrop, the light hits the water-to-air interface. A rainbow will only be seen if this happens, otherwise the light will continue out the other side of the raindrop. In addition,  just as the light changed speed as it entered the raindrop, its speed changes again as it leaves. Here, the light is moving from a more dense medium to a less dense medium. As it does so, it speeds up and its path bends. Finally, as the rays are refracted once again, the various wavelengths are effected to different extents. The overall result of this is increased separation of the component colours of white light.