IBN AL-HAYTHAM (THE FATHER OF OPTICS)

Known in the West as Alhazen, Ibn al-Haytham was the first person to test hypotheses with verifiable experiments, developing the scientific method more than 200 years before European scholars learned of it—by reading his books.
Ibn al-Haytham proved that light travels in straight lines, gave the first clear description and correct analysis of the camera obscura and pinhole camera and built the world's first camera obscura, developed a highly successful theory which explained the process of vision as rays of light proceeding to the eye from each point on an object, which he proved through the use of experimentation.
He is described as the "world's first true scientist".He is also considered to be the founder of experimental psychology for his approach to visual perception and optical illusions.

1. IBN AL-HAYTHAM
Known in the West as
Alhazen, Alhacen, or Alhazeni, Ibn al-
Haythamwas the firstperson to test
hypotheses with verifiable
experiments, developing the scientific
methodmore than 200years
beforeEuropeanscholarslearned of it—
by reading his books.
He was also nicknamed Ptolemaeus Secundus("Ptolemy
the Second").
Ibn al-Haytham is regarded as the “father of modern optics”
for his influential Book of Optics(Kitâb al-Manâzir).
(965 in Basra -c. 1039 in Cairo)

2. Ibn al-Haytham proved that light
travels in straight lines using the
scientific methodby carrying out
various experiments with
lenses, mirrors, refraction, and
reflectionin his Book of Optics
(1021).
Ibn al-Haytham was a pioneer in many areas of science,
making significant contributions in varying disciplines.
His pioneering work on number theory, analyticgeometry, and
the link between algebra and geometry, also had an influence
on René Descartes's(1596-1650)geometric analysis and
Isaac Newton's(1643-1727)calculus.
His optical writings influenced many Western intellectuals
such as Roger Bacon(1214-1294), John Pecham(1230-
1292), Witelo(1230-?), JohannesKepler(1571-1630).

3. In his massive study of light and
vision, Kitâb al-Manâzir(Book
of Optics), Ibn al-Haytham
submitted every hypothesis to a
physical test or mathematical
proof.
Besides the Book of Optics, Ibn al-Haytham wrote several
other treatises on optics.
His Risala fi l-Daw’(Treatise on Light) is a supplement to
his Kitab al-Manazir(Book of Optics). The text contained
further investigations on the properties of luminanceand its
radiant dispersion through various transparentand
translucentmedia.
He also carried out further examinations into anatomyof the
eye and illusions in visual perception.

4. Ibn al-Haytham also gave the first
clear descriptionand correct analysis
of the camera obscura and pinhole
cameraand built the world's first
camera obscura.
Ibn al-Haythamwas the first to demonstrate this with his lamp
experiment where several different light sources are arranged
across a large area. He was thus the first to successfully
project an entire image from outdoors onto a screen indoors
with the camera obscura.
While Aristotle, Theon of Alexandria(335-405), Al-Kindi(801-
873)and Chinese philosopher Mozi(470-391 B.C.)had earlier
described the effects of a single light passing through a
pinhole, none of them suggested that,what is being projected
onto the screen is an image of everything on the other side of
the aperture.

5. Two major theories on vision prevailed in
classical antiquity.
The first theory, the emission theory, was
supported by such thinkers as
Euclid(323-283 B.C.)and Ptolemy(90-
168), who believed that sight worked by
the eye emitting rays of light.
The second theory, the intromission theorysupported by
Aristotle(384-322 B.C.)and his followers, had physical forms
entering the eye from an object.
Ibn al-Haytham argued that the process of vision occurs
neither by rays emitted from the eye, nor through
physical forms entering it.
He instead developed a highly successful theory which
explained the process of vision as rays of light proceeding to
the eye from each point on an object, which he proved
through the use of experimentation.

6. Opticswas translated into Latin by an
unknown scholar at the end of the 12th
century or the beginning of the 13th
century. This work enjoyed a great
reputation during the Middle Ages.
His Book of Opticshas been ranked with
Isaac Newton'sPhilosophiae Naturalis
Principia Mathematicaas one of the most
influential books in the history of physics,
for starting a revolution in optics and visual
perception.
He is described as the "world's first true scientist".He is
also considered to be the founder of experimental
psychologyfor his approach to visual perception and optical
illusions.

7. Ibn al-Haythamwas a pioneer in many areas of
science, making significant contributions in varying
disciplines.
According to medieval biographers, Ibn al-Haytham wrote
more than 200works on a wide range of subjects,of which
at least 96of his scientific works are known.
Most of his works are now lost, but more than 50 of them
have survived to some extent. Nearly half of his surviving
works are on mathematics, 23 of them are on astronomy,
and 14 of them are on optics, with a few on other subjects.