ABU ALI HASAN IBN AL-HAITHAM (ALHAZEN)
| (965 - 1040 C.E.) |
by Al-Haitham conducted experiments on the propagation of light and colors, optic illusions and reflections. He examined the refraction of light rays through transparent medium (air, water) and discovered the laws of refraction. He also carried out the first experiments on the dispersion of
light into its constituent colors. In detailing his experiment with spherical segments (glass vessels filled with water), he came very close to discovering the theory of magnifying lenses which was developed in Italy three centuries later. It took another three centuries before the law of sines was proposed by Snell and Descartes.
His book Kitab-al-Manazir was translated into Latin in the Middle Ages, as also his book dealing with the colors of sunset. He dealt at length with the theory of various physical phenomena such as the rainbow, shadows, eclipses, and speculated on the physical nature of light.
Roger Bacon (thirteenth century), Pole Witelo (Vitellio) and all Medieval Western writers on Optics base their optical work primarily on Al-Haitham's 'Opticae Thesaurus.' His work also influenced Leonardo da Vinci and Johann Kepler. His approach to optics generated fresh ideas
and resulted in great progress in experimental methods.
Al-Haitham was the first to describe accurately the various parts of the eye and gave a scientific explanation of the process of vision. He contradicted Ptolemy's and Euclid's theory of vision that the eye sends out visual rays to the object of the vision; according to him the rays originate in the object of vision and not in the eye. He also attempted to explain binocular vision, and gave a correct explanation of the apparent increase in size of the sun and the moon when near the horizon. He is known for the earliest use of the Camera obscura. Through these extensive researches on optics, he has been considered as the father of modern Optics.
In Al-Haitham's writings, one finds a clear explanation of the development of scientific methods as developed and applied by the Muslims, the systematic observation of physical phenomena and their relationship to a scientific theory. This was a major breakthrough in scientific methodology,
as distinct from guess work, and placed scientific study on a sound foundation comprising systematic relationship between observation, hypothesis and verification.
Al-Haitham, known in the West as Alhazen, is considered as the father of modern Optics. Abu Ali Hasan Ibn al-Haitham was one of the most eminent physicists, whose contributions to optics and the scientific methods are outstanding. Ibn al-Haitham was born in 965 C.E. in Basrah (present Iraq), and received his education in Basrah and Baghdad. He traveled to Egypt and Spain. He spent most of his life in Spain, where conducted research in optics, mathematics, physics, medicine and development of scientific methods.