1. Ibn Al-Haitham (Alhazen) – The Father of Optics An ACE project by Bryan Yan 2I102

2. Who is he? Muslim Scientist Lived during “High point of Islamic Civilization” Made great contributions to physics, mathematics, astronomy and optics Born in Barsa Died at 74 in Cairo Known for his “Book of Optics”

3. Key Contributions Concluded that light enters our eyes and not emitted from them Pinhole Camera Visual Perception of Optical Illusions

4. How do we see? – Past Theories Emission theory Supported by Euclid and Ptolemy Believed that light was emitted from our eyes

5. How do we see? – Past Theories Intermission theory Supported by Aristotle and his followers Believed that physical particles enter our eyes from an object

6. How do we see? Disputing Past Theories Light cannot reach astronomical objects once we open our eyes We are blinded by bright light

7. How do we see? – Accepted Theory (Basis) Proved that light traveled in straight lines Reduced reflected and refracted light rays into vertical and horizontal components Pinhole Camera (more about this later)

8. How do we see? – Accepted Theory Unified version of geometrical optics and philosophical physics to form modern physical optics Images are inverted in our eyes The eye is a medium and lens, neither an emitter or receiver

9. Pinhole Camera – What? Simple camera without lens With a single small aperture Usually a box, but can be done with two white cards of which one has the hole

10. Pinhole Camera – When? Where? 1021 AD In “Book of Optics”

11. Pinhole Camera – How? Light passes through the small hole to form an inverted image on the screen The image is dim and small, but sharp

12. Pinhole Camera – Why? Pinhole acts as a lens Light from surroundings pass through the pinhole, captured on a point on the screen Light from above is captured below and vice versa

13. Pinhole Camera – Link? Similar concept to eye Inverted and sharp image

14. Moon Illusion – Introduction Moon appears larger near the horizon than it does while higher up in the sky Illusion still debated Alhazen’s reasoning most widely available and accepted

15. Moon Illusion – Alhazen’s Principle Judging the distance of an object depends on There being an uninterrupted sequence of intervening bodies between the object and the observer

16. Moon Illusion – Alhazen’s Conclusion When the Moon is high in the sky there are no intervening objects, so the Moon appears close The perceived size of an object of constant angular size varies with its perceived distance

17. References http://en.wikipedia.org/wiki/Alhazen http://www.ibnalhaytham.net/ http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Haytham.html http://harvardmagazine.com/2003/09/ibn-al-haytham-html http://www.britannica.com/EBchecked/topic/738111/Ibn-al-Haytham http://en.wikipedia.org/wiki/Pinhole_camera http://en.wikipedia.org/wiki/Camera_obscura http://www.muslimheritage.com/topics/default.cfm?articleID=382 http://inventors.about.com/od/pstartinventions/a/stilphotography.htm http://lecerveau.mcgill.ca/flash/capsules/articles_pdf/moon_illusion.pdf http://islamsci.mcgill.ca/RASI/BEA/Ibn_al-Haytham_BEA.htm http://www.ishim.net/ishimj/4/10.pdf http://www.newworldencyclopedia.org/entry/Ibn_al-Haytham http://www.iis.ac.uk/view_article.asp?ContentID=106742 http://www.nei.nih.gov/health/eyediagram/images/NEA09.gif http://en.wikipedia.org/wiki/Emission_theory_(vision) http://www.popsci.com.au/galleries/craziest-scientific-theories/emission- theory/6a00d83542d51e69e20120a932bfac970b-500wi_20111012154439_Resized.jpghttp://www.popsci.com.au/galleries/craziest-scientific-theories/emission- theory/6a00d83542d51e69e20120a932bfac970b-500wi_20111012154439_Resized.jpg http://memegenerator.net/instance/13469306 http://images2.wikia.nocookie.net/__cb20081114033730/uncyclopedia/images/1/11/BrightLight.jpg

18. References (Continued) http://images.tutorvista.com/content/feed/tvcs/rectilinear-propagation-of-light.jpeg http://www.healthyeyes.org.uk/index.php?id=2 http://www.bbc.co.uk/schools/scienceclips/ages/10_11/see_things_whatnext.shtml http://www.accessexcellence.org/AE/AEC/CC/vision_background.php http://www.pediatriconcall.com/kidscorner/yourbody/our_eyes.aspx http://www.quora.com/Human-Brain/How-can-we-see-images-in-our-mind http://en.wikipedia.org/wiki/Physical_optics http://www.yorku.ca/eye/invert.gif http://en.wikipedia.org/wiki/Aperture http://en.wikipedia.org/wiki/File:Pinhole-camera.svg http://www.nei.nih.gov/healthyeyes/eye_images/Normal.gif http://www.islamic-study.org/iais-images/al-haytham-optics%20book.gif http://www.thegeminigeek.com/wp-content/uploads/2010/03/Pinhole-Camera.jpg http://www.curriculumbits.com/physics/how-does-a-pinhole-camera-work/ http://wiki.answers.com/Q/How_does_a_Pinhole_camera_work http://wwwx.cs.unc.edu/~sud/courses/comp235/pinhole-principle.gif http://cw.psypress.com/zaidel/images/figure3_4big.jpg http://www.derekshirlaw.co.uk/wp-content/uploads/2012/02/moon.jpg http://en.wikipedia.org/wiki/File:Harvest_moon.jpg http://people.umass.edu/~blaylock/p284/cl0024_hst.gif