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Physics First: Nature and Behavior of Light Units

Optics ("appearance" in ancient Greek) includes the behavior and properties of light and its interaction with matter. The study of optics includes understanding the behavior of visible, infrared and ultraviolet light. Because light is an electromagnetic wave, these events occur in X-rays, microwaves, radio waves, and other forms of radiation. Optics is also electromagnetism that can be described by the quantum nature and electromagnetic description of light.

  Behavior of Light (9)

Lesson Plans:

This multimedia lesson/activity integrates a hands-on prism lab, a Java simulation on light refraction, and an historical vignette on Isaac Newton's classic study of prisms.  It is appropriate for middle and high school, and can be adapted for more advanced students by extending the study to the Refractive Index and the visible light spectrum.  Overall, a nicely cohesive introduction to prepare students for further study of rainbows.

Item Type: Multimedia Lesson
Level: Grades 6-9
Duration: One Class Period

If your students think studying optics would be boring, wait until they try building their own spectroscopes and watching light refract through Jello Jigglers.  This resource is a set of 16 low-cost lesson/labs designed as an overview of the behavior of light.  For the 9th grade physical science class, try the explorations on light spectra, reflection, and refraction.  For more advanced students, we suggest the labs on diffraction, polarization, and fluorescence.  The lens labs would be appropriate for both.

Activities:

San Francisco's Exploratorium Museum has compiled this collection of more than 40 affordable, simple classroom experiments related to light.  The activities cover a wide range of topics relating to the behavior of light, from reflection/refraction and diffraction to pinhole optics and polarization.  All are miniature versions of some popular exhibits at the museum.

Want to do a unit on light, but time is limited?  This is a solid, well-designed set of 6 activities intended to be used as learning centers in the physical science classroom.  Students explore phenomena such as diffraction, transparency and translucency, rainbows, refraction, and more.  Materials are all inexpensive and easy to acquire.  Allow two days.

References and Collections:

This is an easy-to-read time line of milestones in optics, highlighting contributions of key people in the field.  It begins with the investigations of the early Greeks, progresses through early telescopes and microscopes, and continues the journey from ray optics and wave optics through the revolutionary advances of the 20th Century.

Try this great web site for a very broad selection of activities and background information on the science of light.  Your students can look at 12 optical illusions, play around with dozens of interactive simulations related to light behavior, and find scientific definitions of all the vocabulary associated with light and optics.  There is a full section devoted to teachers, with lesson plans and background information on color, light reflection and refraction, rainbows, geometric optics, human vision, and the wave nature of light.

Content Support For Teachers:

When light waves travel from one medium to another, the waves may undergo a phenomenon known as refraction.  It often looks like the light is "bending".  This tutorial combines simulations with illustrated background information to explain how light behaves as it refracts.  An understanding of this process is an important foundation to learning about lenses and microscopes.

This standards-based resource offers easy-to-use worksheets and a structured questioning pattern that guides new and pre-service teachers through a hands-on, inquiry-based course that models best practice instructional models.  This particular volume deals with the behavior of light, color perception, and the electromagnetic spectrum.  Available for purchase from the AAPT online bookstore.

Student Tutorials:

To understand the basics of light, students may need help to see that "light" consists of so much more than what we see with our eyes.  This is an excellent tutorial from Johns Hopkins University designed especially to make these concepts understandable to middle school and high school students.  We suggest starting with this section: The Basics of Light, then move into tutorials on the electromagnetic spectrum.

  Ray Optics -- Reflection and Refraction of Light (16)

Lesson Plans:

A collection of more than 50 hands-on  experiments designed to introduce high school and middle school students to geometric optics, also known as the ray model of light.  Topics include reflection, refraction, pinhole cameras, the human eye, color and the visible spectrum, optical equipment, and ray streaks.  Each lab has background information, safety guidelines, and tips for use in the classroom.

Not sure whether to use a ray box or another light source for your geometric optics experiments?  This web page, by the authors of Practical Physics, gives advantages of both for varying lab situations.

An inquiry-based activity designed to help students understand the Law of Reflection (the angle of the incoming incident light ray equals the angle of the reflected ray).  The only materials required are a mirror, paper, and masking tape.  The web page also includes a Java simulation on angles of reflection.

This is an award-winning module created specifically for use with the PhET simulation Geometric Optics.  It includes a lesson plan with step-by-step printable student directions, background information on convergent lenses, and a full set of Power Point clicker questions (with answers) for formative assessment.  We suggest using it after students have explored concave/convex lenses in a hands-on lab (see Practical Physics Optics Labs above).

Activities:

This resource can double as a tutorial and student activity in the computer lab.  The students interactively explore the Law of Reflection, concave/convex mirrors, and how surface texture affects the way light is reflected.  Try teaming it with the lesson plan above: "Mirror, Mirror On The Wall".

A great follow-up simulation after doing a classroom lab on converging lenses.  Your students choose from four "objects" (pencil, star, smiley face, and arrow).  They can change the curvature of the convex lens, adjust the focal length, and move the object to get a feel for how light refracts through a converging lens.  Don't miss the step-by-step lesson and Power Point clicker questions created by a high school teacher specifically for use with this simulation (see Lesson Plans above).

A very well-designed problem set by the PhET team, intended specifically for use with the simulation Geometric Optics (see item directly above).  It contains a two-page student guide with explicit directions on using the settings within the simulation.  It ends with a 10-point assessment to gauge student understanding of light refraction through a convex lens.

These animations were developed by the author of the respected Physics Classroom web site to help students comprehend reflection and refraction.  Each one is accompanied by a full text explanation and links to additional resources on geometrical optics.  This particular section is appropriate for grades 7-9 with some scaffolding by the teacher.

Students experimenting with pinhole cameras are often amazed to see an inverted image at the back of the box.  Often, they are confused about why the pinhole image is upside down, but we see things rightside-up with our eyes.  The difference is that the pinhole actually projects rays of light  through the hole to specific points on the back of the box. The lenses in our eyes act to converge light rays together into a common focus.  This lesson is a great springboard to help students understand the ray model of light.  **NOTE:  Pinhole camera can be constructed by the student.  See the resource directly below for step-by-step directions on building one out of an oatmeal box.

A pinhole camera is a camera without a lens.  It lets light into a sealed box through a tiny aperture (pinhole) that projects an inverted image onto photo-sensitive paper.  Virtually any container capable of excluding light can become a pinhole camera.  This resource gives explicit directions on how to build one out of an oatmeal box, take photos with it, and even develop them in a darkroom.  Experiments with pinhole cameras help students see how a beam of light projects from a point source to a particular spot.  The accumulation of all the rays passing through the pinhole forms an image at the film plane.  This is a basic principle of the ray model of light.  Did we mention it's fun because the camera really works?

A very simple yet enlightening simulation for exploring the function of a pinhole camera.  The applet draws lines from five points on a source through the pinhole.  Students can see the path of each ray of light and the resulting inverted image.  We suggest letting students play with this applet AFTER they have completed one of the labs above on pinhole cameras.

Content Support For Teachers:

In this item devoted to the physics of sight, the author explores how the human eye is able to refract light to produce a focused image.  The inclusion of lens and magnification calculations focuses the material specifically for the physics teacher.

This interactive tutorial offers teachers a way to build content knowledge of light reflection.  By integrating four Java simulations, the resource is fun and allows the user to more readily "see" what is happening as light reflects off both a flat and a curved surface.  Also includes more advanced concepts such as total internal reflection.

When light waves travel from one medium to another, the waves may undergo a phenomenon known as refraction.  It often looks like the light is "bending".  This tutorial combines simulations with illustrated background information to explain how light behaves as it refracts.  An understanding of this process is an important foundation to learning about lenses and microscopes.

Student Tutorials:

A bi-convex thin lens is the type of lens used in eyeglasses, magnifying glasses, and single-lens cameras.  They work in accordance with simple principles of geometry.  This simulation-based tutorial lets students move the virtual lens back and forth on an optical axis.  They can observe the effects of the changing distances on the magnification produced by the lens.  The text tutorial further explains the fundamentals to prepare students to solve problems involving focal length and magnification.

A great companion tutorial to the item directly above.  This simulation by the same author lets students change the object size and focal length to see how these variables affect the image formed by a bi-convex lens.  The lens equation is displayed at the same time: values automatically change with the changing variables.

  Microscopy and Optical Devices (9)

Activities:

Students experimenting with pinhole cameras are often amazed to see an inverted image at the back of the box.  Often, they are confused about why the pinhole image is upside down, but we see things rightside-up with our eyes.  The difference is that the pinhole actually projects rays of light  through the hole to specific points on the back of the box.  Lenses, which we have in our eyes, brings light rays together into a common focus.  This lesson is a great springboard to help students understand the ray model of light.  **NOTE:  Pinhole camera can be constructed by the student.  See the resource directly below for step-by-step directions on building one out of an oatmeal box.

A pinhole camera is a camera without a lens.  It lets light into a sealed box through a tiny aperture (pinhole) that projects an inverted image onto photo-sensitive paper.  Virtually any container capable of excluding light can become a pinhole camera.  This resource gives explicit directions on how to build one out of an oatmeal box, take photos with it, and even develop them in a darkroom.  Experiments with pinhole cameras help students see how a beam of light projects from a point source to a particular spot.  The accumulation of all the rays passing through the pinhole forms an image at the film plane.  This is a basic principle of the ray model of light.  Did we mention it's fun because the camera really works?

A very simple yet enlightening simulation for exploring the function of a pinhole camera.  The applet draws lines from five points on a source through the pinhole.  Students can see the path of each ray of light and the resulting inverted image.  We suggest letting students play with this applet AFTER they have completed one of the labs above on pinhole cameras.

What do scientists see under a scanning electron microscope (SEM)?  Find out first-hand in this award-winning Java applet.  Students can choose from 14 specimens, including a cockroach, jellyfish, gecko foot, pollen grain, and more.  They will first adjust the focus, contrast, and brightness of the specimen to optimize its appearance.  Then they control a slider to increase the magnification in steps.....up to 10,000 times.  This activity would work well in the computer lab or in a classroom digital projection system.

References and Collections:

This site is a large collection of high school and middle school curricular materials on optics and microscopy.  Users can link to comprehensive tutorials on basic microscopy, digital imaging, optical microscopy, and more.  Text information is supplemented with innovative Java-powered virtual microscopes that allow users to explore focus, magnification, and translation in a real-life manner.

Student Tutorials:

How does a simple lens work?  This interactive, voice-narrated tutorial gives beginning students an introduction to both concave and convex lenses.  It provides detailed diagrams of how they refract light, converging or diverging the beam depending upon the shape of the lens.  Included are self-guided question-and-answer sets.

This Java-based tutorial introduces students to concave and convex lens characteristics and explains how each type of lens works to produce convergence or divergence of light.  It would be a great warm-up activity before a class lab on lenses and magnification.

Professionally produced 15-minute video explores how light interacts with lenses to form images. It's the best resource we've found to explain the difference between real and virtual images.....a crucial foundation for understanding geometrical optics. Appropriate for 9th grade physical science and adaptable as a refresher for high school physics.

Item Type: Video
Level: Grades 9-12
Duration: 15 minutes

2nd in series of four well-executed videos on how light interacts with lenses to form images. This one takes a deep look at light refraction by convex lenses. Appropriate for high school, but the first half could be adapted for middle grades. If your students don't get how incident light rays can converge to a point, they will gain a solid understanding from this video.

Item Type: Video
Level: Grades 8-12
Duration: 15 minutes

  The Wave Nature of Light (3)

Activities:

Students often think of "light" only as that which the human eye can perceive.  This excellent resource introduces students to the entire electromagnetic spectrum (which,  of course, includes visible light.)  Students view models of photon emission/absorption, create a model photon beam, and interactively explore how light intensity is related to the frequency of light.

Content Support For Teachers:

Is light a particle or a wave?  The answer is: it has characteristics of both.  This is one of the best tutorials we have found to explain the wave-particle duality of light in terms a non-physicist can understand.  Four interactive simulations demonstrate how a beam of light behaves when it is reflected, refracted, diffracted around an object, and combined in a double-slit experiment.  The accompanying explanations would be an excellent resource for teachers who want to learn more about the wave nature of light.

Student Tutorials:

How do we know that light behaves as a wave as well as a particle?  Young's classic double-slit experiment demonstrated the concept more than 200 years ago, establishing the wave theory of light.  This interactive tutorial is an excellent introduction to the wave nature of light.  It explains Young's experiment in a coherent way and includes voice narration, especially helpful for students with disabilities.

  Electromagnetic Radiation and the Spectrum (7)

Lesson Plans:

In this exceptional inquiry-based lesson plan, students discover that there is radiation other than visible light being emitted from the sun.  They build their own observational device out of a cardboard box, prisms, and alcohol thermometers......replicating the historical experiment in which William Herschel "accidentally" discovered infrared radiation in 1800.  Includes warm-up questions, lab guide, assessments, and teaching tips.

Activities:

Want to teach about light but haven't ever studied optics or electromagnetic radiation?  This resource is a great start.  Prepare to be surprised at the humorous-but-informative background info, the real-life analogies, and the ideas for inexpensively teaching these concepts to your physical science students.  The lesson plan on making a rainbow is appropriate for middle school.

All objects with a non-zero temperature will emit infrared radiation, but we cannot see it with our eyes.  This excellent collection of images produced with infrared photography allows students to "see" temperature differences and variations in heat intensity.  They will be looking at a hot cup of coffee, warm-blooded and cold-blooded animals, ice cubes, and hot springs. For an inquiry-based lab to extend this exploration, see "Science NetLinks: The Herschel Experiment" in Lesson Plans above.

Over the past 100 years, there has been a revolution in our ability to understand light and its various forms of radiation. This image collection, produced especially for Teachers' Domain, is a fascinating glimpse of stars, the Milky Way, and the crab nebula, photographed using four different telescopes.  Students can compare how these objects look in visible light, infrared, x-ray, and radio imaging.

This beautifully-presented NASA resource introduces students to the wonder of electromagnetic waves and their behaviors. Each segment of the spectrum is described & illustrated, and accompanied by a video clip. Don't miss the newly available EMS book, "Tour of the Electromagnetic Spectrum, available for online viewing or free download.

Student Tutorials:

To understand the basics of light, students may need help to see that "light" consists of so much more than what we see with our eyes.  This is an excellent tutorial from Johns Hopkins University designed especially to make these concepts understandable to middle school and high school students.  We suggest starting with this section: The Basics of Light, then move into tutorials on the electromagnetic spectrum.

A great resource to introduce beginners to the idea of light as part of a much larger spectrum of electromagnetic radiation.  Students work at their own pace to learn about all 7 sections of the Spectrum, from long-wavelength radio waves through the mysterious short-wavelength gamma rays.  They will see for themselves that visible light is only a small part of the whole.

  Visible Light and Color (8)

Lesson Plans:

Did you know that the three primary colors of light are red, green, and blue (not yellow).  In this unique, award-winning unit on color, students investigate why the traditional color wheel cannot be applied to human perception of color.  They will learn how objects  absorb one or more colors of light to produce the dazzling array of colors we see with our eyes.  **NOTE: The unit was developed for use with a set of unique hands-on lab materials, which may be purchased at low cost from the publisher.

For students who have explored the basics of color mixing, this is an excellent unit to continue their investigation into the subject.  This comprehensive module (same authors as the module above) takes students on a hands-on journey of the origin of colors in solids, liquids, and gases.  They will explore the color of fireworks, why the sky is blue, how glowsticks and fireflies produce phosphorescent light, and how LED's work.

Activities:

A great Java-based activity to help middle schoolers understand how the three primary colors of light (red, green, and blue) combine to produce multiple colors.  In one simulation, students can adjust the intensity of each color.  In the second, they can add filters to see what happens to the resulting color.  The PhET team created an excellent lesson to go with this simulation.  Find it directly below.

A high school teacher created this worksheet/assessment specifically for use with the PhET simulation "Color Vision" (see above).  It gives step-by-step directions to focus students on the fundamentals of color addition and subtraction, with opportunities to construct hypotheses as they go.  Allow one class period with access to internet.

Using a spectroscope, students can see that a single color of light is really comprised of a combination of colors, called a spectrum.  This fun activity by the Exploratorium Museum shows them how to build a spectroscope out of a shoebox and other low-cost materials.  The key "ingredient" of the spectroscope is a diffraction grating, a device with multiple evenly-spaced parallel slits to let light through.  Don't worry...the diffraction grating material can be cheaply obtained.

The colors red, green, and blue are classically considered the primary colors of light because they are fundamental to human vision. All other colors of the visible light spectrum can be produced by adding different combinations of these three colors. This Java simulation lets students move and overlay three circles colored red, green, and blue.  Combine any two and produce the complementary colors of light (cyan, magenta, and yellow).  Combine all three and the result is white light.  We suggest introducing this simulation alongside the one directly below on subtractive (complementary) colors.

The complementary colors (cyan, yellow, and magenta) are also commonly referred to as the primary subtractive colors because each can be formed by subtracting one of the primary additives (red, green, and blue) from white light. This tutorial explores how the three primary subtractive colors interact with each other, both in pairs or all together.  Interestingly, when all three are mixed, the result is black (the absence of light). We recommend introducing this tutorial after the simulation directly above on primary additive colors.

Student Tutorials:

To fully understand color perception, students need to shift gears from the traditional color wheel model they learned in grade school. This is a fun, high-quality tutorial that explains why the RGB primary colors of light (red, green, blue) are different from the primary colors of pigment and paint. It's because the photoreceptors in our eyes respond to wavelengths in certain regions: red, green, and blue. These colors then combine to form the complementary colors of light: cyan, magenta, and yellow. Your students will enjoy the four Java simulations that accompany the tutorial.

  The Eye (2)

Activities:

We guarantee that this video-based activity will fascinate your students as they learn about the anatomy of the eye.  A teenage narrator dissects a real cow eye (with optic nerve attached) in a 12-part Flash video.  Students will get an up close & personal view of the cornea, iris, lens, and retina as they control the pace of the videos.  Also includes an eye diagram and illustrations that show how the eye refracts light and sends messages to the optic nerve.

Student Tutorials:

This five-part tutorial on the human eye is part of the highly-regarded Physics Classroom web site.  Students work at their own pace to gain understanding of the complex physical and neural mechanisms that interact to produce human vision.