Kamal al-Din al-Farisi

A disciple of the Maragha school, in Tanqih al-Manazir he unified Ibn al-Haytham's book with Qutb al-Din al-Shirazi's and completed their method. He gave the first complete physical explanation of the rainbow through reflection and refraction inside a water drop, proved it with a water-filled spherical flask experiment, and studied sunset colours.