A Study on the Physical Nature of the Rainbow

The rainbow is common natural phenomenon after the rain.Understanding the physical nature of the rainbow can help to deepen our scientific knowledge of natural phenomena.This article gives brief introduction to dispersion and explains the causes of the scene as described in the poetic lines a setting sun after the rain,a dancing rainbow in the sky.It addresses the issues concerning the history of human knowledge of rainbow,the simple physical nature of rainbow,geometrical inference and the polarization state of the rainbow.Adopting the method of combining number with geometrical figure,we explain the physical mechanism of the visible features of rainbow and its physical nature.