In the state of Hawaii, we are blessed with the beautiful tropical nature. I have seen so many rainbows in my life that I just think of rainbows as another thing. I don’t realize how lucky I am to see a rainbow about everyday because I know the people in the mainland are not blessed to see such a beautiful rainbow like ours. So today I would like to explain what a rainbow is and how it is created.
Light is made up of a collection of many colors: red, orange, yellow, green, blue, indigo, violet. That is why a prism can take in white light on one side and produce its own mini-rainbow on the other side. To understand rainbows, you have to start by understanding what is happening inside a prism to let it separate white light into its colors.
The dispersion of colors in a prism occurs because of something called the refof the glass. Every material has a different refractive index. When light enters a material (for example, when light traveling through the air enters the glass of a prism), the difference in the refractive index of air and glass causes the light to bend. The angle of bending is different for different wavelengths of light. As the white light moves through the two faces of the prism, the different colors bend different amounts and in doing so spread out into a rainbow.
HI Physics 808 