# Physics in Context - 2nd Edition

## Chapter 10: Light and Optical Systems

Some links are repeated for use with more than one lesson.

### 10.1  Ray Optics: Reflection and Refraction

Light and Optics Module
http://www.asu.edu/courses/phs208/patternsbb/PiN/info/act/activities.shtml
This site is part of Patterns in Nature course from Arizona State University. This page provides links to several optics activities. Although some reference an "Optics Kit," you might have the required elements available to you. If not, at least explore and try the other activities.

Reflection and Refraction Java Applet
http://www.phy.ntnu.edu.tw/java/light/flashLight.html
Java applet that shows reflection and refraction at the boundary between water and air. You can select whether the light shines from the air or the water side of the boundary and the angle at which it is directed.

Reflection and Refraction of Light
http://physics.bu.edu/~duffy/PY106/Reflection.html
A brief tutorial on the reflection and refraction of light. Example problems with concave and convex mirrors are worked out.

Total Internal Reflection and Lenses
http://physics.bu.edu/~duffy/PY106/Lenses.html
Example problems are provided.

The Physics Classroom: Ray Optics
http://www.physicsclassroom.com/mmedia/optics/lr.cfm
This series of lessons at the Physics Classroom uses rays to trace line of sight, reflections, and image formation with mirrors. Practice problems are included.

The Physics Classroom: Refraction and the Ray Model of Light
http://www.physicsclassroom.com/class/refrn
This extensive set of lessons uses the ray nature of light to explain how light refracts at planar and curved surfaces. Snell's law and refraction principles are used to explain a variety of real-world phenomena. Refraction principles are combined with ray diagrams to explain why lenses produce images of objects.

The Physics Classroom: Reflection and the Ray Model of Light
http://www.physicsclassroom.com/class/refln
This extensive set of lessons uses the ray nature of light to explain how light reflects off of planar and curved surfaces to produce both real and virtual images. The nature of the images produced by plane, concave, and convex mirrors are thoroughly illustrated.

Reflection and Refraction of Light Waves by Huygens' Principle
http://www.walter-fendt.de/ph14e/huygenspr.htm
This interactive applet recreates the explanation of reflection and refraction of light used by Huygens, who believed light traveled as a wave. (Requires Java.)

Geometric Optics Simulation
This interactive applet from PhET allows you to simulate the ray tracing for a typical lens activity to analyze the optics of a thin lens. You can move the object and lens, and vary the characteristics of the lens. (Requires Java.)

Bending Light Simulation
This interactive applet from PhET allows you to simulate the ray tracing for a typical refraction activity to apply Snell’s Law, both for a stationary boundary as well as a variety of prisms. You use a built-in protractor to measure the resulting angles, can vary the source and media angles, and can change the media. (Requires Java.)

Optics Applets
http://webphysics.davidson.edu/applets/optics/intro.html
These interactive applets cover more advanced optics topics such as spherical aberration, thick lenses, and total internal reflection, e.g., fiber optics. A link to documentation provides support for programmers. (Requires Java.)

Total Internal Refection and Critical Angle
http://www.physicsclassroom.com/class/refrn/Lesson-3/Total-Internal-Reflection
These lessons from the Physics Classroom chapter on Refraction present angles of reflection and refraction in a practical way, and include questions for a self-check of your understanding.

Howstuffworks: How Fiber Optics Work
http://www.howstuffworks.com/fiber-optic.htm
Fiber optics work by total internal reflection. This site explains fiber optics and their applications.

The Anatomy of the Eye
http://www.physicsclassroom.com/Class/refrn/U14L6a.html
A physics tutorial written for high school students.

The Eye
http://hyperphysics.phy-astr.gsu.edu/hbase/ ligcon.html
Under "Light and Vision/Vision/" are generous models and diagrams of the eye and it's function in image formation.

### 10.2  Wave Optics: Interference and Diffraction

Theories of Light
http://www.thestargarden.co.uk/NewtonAndLight.html
This series of pages discusses the competing theories and discoveries relating to light: the wave theory from Huygens versus the corpuscular (or particle) theory from Newton, measuring the speed of light, discovering the electromagnetic properties of light, and so forth.

Christiaan Huygens Biographies.

• Huygens: Mathematician, Astronomer, and Physicist
http://biography.yourdictionary.com/christiaan-huygens
An easy-to-read biographical summary touching on the many areas of scientific thinking of Huygens: telescopes and astronomy, pendulum clocks, conservation of energy in collisions, and the wave theory of light.
• Huygens: A Leading Scientist of His Time
http://en.wikipedia.org/wiki/Christiaan_Huygens
A Wikipedia summary of the life and accomplishments of Huygens, one of the early proponents of the wavelike nature of light, as well as competing ideas for describing laws of motion, collisions, and pendulum clocks.

Young, Thomas (1773 - 1829) — From Eric Weisstein's World of Scientific Biography
http://scienceworld.wolfram.com/biography/Young.html
Short biography of Thomas Young

Reflection and Refraction of Waves
http://www.walter-fendt.de/ph14e/huygenspr.htm
This applet is an attempt to explain the reflection and the refraction of waves by Huygens' principle.

Bragg's Law and Diffraction
http://www.eserc.stonybrook.edu/ProjectJava/Bragg/
Discusses Bragg's law and diffraction and an interactive applet demonstrates how features of a crystal’s structure can be deduced by measuring the diffraction pattern formed by reflecting x-rays. (Requires Java.)

Single-Slit Diffraction
http://www.phys.hawaii.edu/~teb/optics/java/slitdiffr/
This applet shows the simplest case of diffraction, single-slit diffraction. You can vary the width of the slit and the color of the light.

Diffraction of Light Through a Single Slit
http://www.walter-fendt.de/ph14e/singleslit.htm
The interactive applet on this page explores and measures the diffraction of light passing through a single slit, when varying the light wavelength and the width of the slit.

Interference of Light Through a Double Slit
http://www.walter-fendt.de/ph14e/doubleslit.htm
The interactive applet on this page explores and measures the interference of light passing through a double slit, when varying the light wavelength and the separation of the pair of slits.

Diffraction Grating Calculator
http://www.calctool.org/CALC/phys/optics/grating
This page includes a calculator for predicting the resulting pattern from a diffraction grating, where the user specifies the grating spacing, wavelength of light, and incident angle.

Howstuffworks: How Light Microscopes Work
http://www.howstuffworks.com/light-microscope.htm
This HowStuffWorks page explains how light microscopes work.

Howstuffworks: How Telescopes Work
http://www.howstuffworks.com/telescope.htm
Lots of interesting information on how a telescope works, the various types of telescopes, and telescope mounts and accessories

Howstuffworks: Why Do CDs Reflect Rainbow Colors?
http://www.howstuffworks.com/question52.htm
This page answers the question of why CDs and soap bubbles reflect rainbow colors in terms of constructive and destructive interference.

Spectrophotometer Simulation
http://www.chm.davidson.edu/java/spec/spec.html
Applet simulating operation of a spectrophotometer. The experiment models emission of photons by a lamp, absorption of those photons by a solute in a sample solution, and detection of the photons by a photomultiplier tube. The photons are represented by little balls (a particulate matter model rather than a wave model). The simulation permits simultaneous use of two different wavelengths.

### 10.3  Laser Light

Discovery of the Electron
http://www-outreach.phy.cam.ac.uk/camphy/electron/electron_index.htm
This series of pages (click Next Page) at this site escorts you through the steps of Thomson's experiments to discover the electron.

ChemTeam: Atomic Structure
http://www.chemteam.info/AtomicStructure/AtomicStructure.html
This page presents links to a series of pages that outlines how our understanding of the atom has evolved, and the contributions of various scientists to this knowledge.

The Atom
http://web.archive.org/web/20010524002612/improbable.org/era/physics/atom.html
Outlines the various models of the atom as held by Aristotle, Dalton, Bohr, de Broglie, and Schroedinger

Ernest Rutherford
The following sites are links to biographical entries.

Sir Joseph John Thomson—Biography
http://www.nobel.se/physics/laureates/1906/thomson-bio.html
The Nobel e-museum's biography of J. J. Thomson

Niels Bohr
The following sites are links to biographical entries.

A Science Odyssey: People and Discoveries
http://www.pbs.org/wgbh/aso/databank/entries/bpbohr.html

The Nobel e-Museum (Bohr)
http://www.nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-bio.html

AtomicArchive: Niels Bohr
http://www.atomicarchive.com/Bios/Bohr.shtml

The Bohr Model of the Atom:
http://www.chemteam.info/Electrons/Bohr-Model-part1.html
A two-page discussion of the work by Niels Bohr to uncover the structure of the atom.

Louis de Broglie
The following sites are links to biographical entries.

Erwin Schrödinger
The following sites are links to biographical entries.

Atom Builder
http://www.pbs.org/wgbh/aso/tryit/atom/
This applet lets you build atoms by creating neutrons and protons and adding electrons. You must keep the particles balanced as you add them or you end up with radioactive isotopes or ions that go off to bond with other ions to form molecules.

Quantum Primer
An excellent piece on the quantum theory of the atom. It is also available as a printable version in Adobe Acrobat.

Quantum Physics
http://hyperphysics.phy-astr.gsu.edu/hbase/quacon
The links on the right side of this page from the Hyper Physics website link to various pages related to topics such as the Bohr theory, quantum numbers, atomic structure, and atomic properties. You can explore these topics and more by linking to additional sites from these pages.

Emission Spectrum of Hydrogen
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch6/bohr.html
This page gives a somewhat historical discussion of efforts to interpret the emission spectrum of hydrogen. Towards the end, it gets rather advanced.

Spectral Lines
This site on Physics 2000 discusses the formation of spectral lines.

#### LASER Sites

Introduction to Lasers
http://micro.magnet.fsu.edu/primer/lightandcolor/lasersintro.html
This page gives an introductory yet technical treatment of how lasers produce and amplify a stimulated form of light into intense and focused beams.

Laser Fundamentals
https://www.fas.org/man/dod-101/navy/docs/laser/fundamentals.htm
This page excerpted from Department of Defense training materials, discusses laser theory and operations, the components of a laser, and wavelengths associated with different types of lasers.

Laser Safety Basics
http://www.grainger.com/content/qt-laser-safety-basics-127
This page covers important terminology and classifications of laser types and intensities, and protective measures necessary to assure your safety.

Introduction to Laser Safety (OSHA)
An introductory-level slide show (view individual slides, or download entire presentation) addressing safety concerns regarding laser light, including laser basics, wavelengths, primary dangers (eyes, skin, etc.), exposure limits, protective procedures and equipment, and so forth.

Laser Basics
http://www.thetech.org/exhibits/online/lasers/Basics/
A colorful, easy-to-read series of pages (click Next) from “The Tech Museum” presenting how lasers work, what they produce, and how they are used.

Laser Simulation
With this applet you create a laser by pumping the chamber with a photon beam, and then manage the energy states of the atoms to control its output. (Requires Java.)

Introduction to Lasers
This series of pages with interactive applets from Physics2000 presents an easy-to-understand development of how lasers work. (Requires Java.)

Howstuffworks: How Lasers Work
http://www.howstuffworks.com/laser.htm
Explains operation of a laser, the different types of lasers, and their applications. Also included is an extensive list of links to outside sources of information.