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History of Optics PHY 108 Fall 2003

History of Optics

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History of Optics. PHY 108 Fall 2003. Early “Optics”. Early “Optics”. “In the beginning God created the heaven and the earth. Now the earth was unformed and void, and darkness was upon the face of the deep; and the spirit of God hovered over the face of the - PowerPoint PPT Presentation

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Page 1: History of Optics

History of Optics

PHY 108 Fall 2003

Page 2: History of Optics

Early “Optics”

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Early “Optics”“In the beginning God created the heaven and the earth. Now the earth was unformed and void, and darkness was upon the faceof the deep; and the spirit of God hovered over the face of thewaters. And God said: ‘Let there be light.’ And there was light.”

Or consider this alternative translation:

“When God began to create the heavens and the earth, while the earth was unformed and void, and darkness was on the face of thedeep, and the spirit of God hovered over the face of the waters,God said, ‘Let there be light.’ And there was light.”

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History of Optics – Early Players

• Aristotle (4th cent. BC)

• Euclid (Alexandria, ca. 300 BC)

• Ptolemy (2nd cent. AD)

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History of Optics – Early Ideas

• Straight-line propagation

• Equal-angle reflection

• Bending of rays at interfaces (“refraction”)

• Vision theories– Objects-to-eye (intromission)

– Vision as a “feeling process” (extramission)

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History of Optics

Euclid (Alexandria, ca. 300 BC) - “Optics”

Early record of the principle that rays of light travel in straight lines.

Wrote about measuring the relative apparentsize of objects by referring to the “angular size.” (A precursor to perspective?)

His theory of vision considered rays of light emanating from the eyes of the observer.

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Euclid

A student learned the first proposition in geometryfrom Euclid’s “Elements” and wanted to know what hewould gain by learning these things. Euclid called hisslave and said disdainfully, “Give this student a coin since he has to make a profit from what he learns.”

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History of Optics

First military applications of optics

Archimedes and the siege of Syracuse(214 B.C.)

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ArchimedesThe Syracusans finally lost to the Romans, and Archimedes was killedby a Roman soldier (because he refused to quit working on a geometrical proof when commanded to do so!?).

Apparently, Archimedeshad only disdain for hisengineering and practicalachievements, never evenbothering to write them down.For him, pure knowledge(geometry, for example) wasthe only worthwhile pursuit.

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Siege of Syracuse

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Siege of Syracuse

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Ptolemy

Ptolemy (2nd century AD, also Alexandria) - Of his works, only an incomplete 12th century

Latin translation survives, which in turn is based on a lost Arabic translation. The title “Almagest” derives from the Arabic version of the Greek superlativemeaning “The Great.”

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The “Dark Ages”

Many Greek works were lost to western Europe for several centuries (ca. 300 - 1300 AD).

Most works survived only in Arabic translations; the scientific culture thrived in Baghdad and other centers of the Islamic world (ca. 800 - 1100 AD).

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Islamic ContributionsAbū Yūsuf Ya’qūb ibn Ishāq Al-Kindī (Baghdad, ca. 850)

Studied Euclid, others; worked to integrate theGreek/Neo-Platonic traditions with Islam.

Hunayn ibn Ishāq (Baghdad, ca. 850)Anatomy and physiology of the eye.

Ibn Sahl – (ca. 980) Calculation of the correct lens shape needed to focus the sun’s rays to a perfect point.

Abū Alī al-Hasan ibn al-Haytham (Basra, Cairo, ca. 1000)Put to rest idea of visual rays; understood many optical principles, such as the “camera obscura.”Synthesized all optical knowledge.

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Eyeglasses?

When do eyeglasses first appear?

Roger Bacon? (13th century)

Umberto Eco’s “The Name of the Rose”

Principles were not understood, however.

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Kepler (ca. 1600) Solves the Problem

He was the first to theoretically understand how imagesare formed by lenses.Kepler still did not have an exact mathematical formulato describe the phenomenon, however.

Museum der Sternwarte Kremsmünster, Austria

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Art and Science• Albrecht Dürer