How many colors are there in the rainbow?

1704, the British scientist Newton published a book called Optics. At that time, prisms were children's toys. He used this toy to study the function of light. He let the sunlight pass through the prism. Therefore, sunlight is divided into several colors. It looks like a rainbow.

However, he said at first that light can be divided into five colors. Later, he recruited an assistant to show him. As a result, he said that the rainbow has seven colors. Newton said, "My eyes are old, so you can see better!" " "

Newton supported the assistant's conclusion because he had a hypothesis in his mind. The structure of light is like a ruler. A scale has seven notes, five diatonic scales and two chromatic scales. The two scales make various melodies together. Without two chromatic scales, there would be no colorful melody.

He thinks that the five colors he found at first are chromatic, and the two colors his assistant found are chromatic. So he decided that there were seven colors in the rainbow.

However, people don't believe Newton's idea now. We know that color has nothing to do with proportion. However, the great scientist said that rainbows have seven colors, and we believe him now.

How many colors are there in the rainbow? Count it yourself. Please look out of the window. Look, a beautiful rainbow appears!