— Being me: what it means to be human P. 14

Place a prism in a beam of white light and see what happens to the light as it passes through. As the light exits on the other side it splits into a rainbow of colors. We like to think we can describe the colors and hence we give them names — red, orange, yellow, green, blue, indigo, and violet. There is, however, no boundary between red and orange, the two merge. The difference in color is due to the wavelength of the light with red light having a longer wavelength than orange. There is, however, no point in the spectrum where you can say that on the one side we have red light and on the other side, orange. But knowing which color of light you are playing with is useful. For example, red light to carries more energy than blue, so you can use red light to keep food warm and blue light in places where we want to see but introduce as little heat as possible.”