Edu 528 Tech Lesson 1

Lesson Title: Multimedia Light Presentation Teacher: Steve Propheter Subject: Physics Time Required: 2 weeks Topic: Light

Grade Level: 11/12

Essential Question: What is Huygen’s Principle? What is diffraction and where is it found? What is Young’s double slit experiment? What is the difference between constructive and destructive interference? What is white light made of? What is refraction of light? What is spectrum of light? ROYGBIV What is interference by thin films? Prerequisites (Prior knowledge) Students should have a good understanding of waves and different properties of waves at this time. They should be able to determine the velocity, frequency, and wavelength of a wave. Stage 1 – Desired Results Content Area Standard(s) (include complete standard, not just standard #) NYS Science Standards Standard 4: The physical setting Key idea 4: Energy exists in many forms, and when these forms change energy is conserved. 4.3 Explain variations in wavelength and frequency in terms of the source of the vibrations that produce them, e.g., molecules, electrons, and nuclear particles. i. compare the characteristics of two transverse waves such as amplitude, frequency, wavelength, speed, period, and phase ii. draw wave forms with various characteristics iii. identify nodes and antinodes in standing waves iv. differentiate between transverse and longitudinal waves v. determine the speed of sound in air vi. predict the superposition of two waves interfering constructively and destructively (indicating nodes, antinodes, and standing waves) vii. observe, sketch, and interpret the behavior of wave fronts as they reflect, refract, and diffract viii. draw ray diagrams to represent the reflection and refraction of waves ix. determine empirically the index of refraction of a transparent medium Key Idea 5: Energy and matter interact through forces that result in changes in motion. 5.3 Compare energy relationships within an atom’s nucleus to those outside the nucleus. i. interpret energy-level diagrams © Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe)) correlate spectral lines with an energy-level1 diagram Intended Learning Outcome (Should define what students will know and be able to do and at what level of mastery they should be able to do it.)

Students will know…

Student will be able to…

Huygen’s Principle

…explain wave fronts and Huygen’s principle accurately 100% of the time

Primary Colors of light Secondary Colors of light

…mix colors of light and determine the resultant color correctly 100% of the time

Primary Colors of Pigment Secondary Colors of Pigment

…explain the difference between colors of light and colors of pigments

Reflection

…determine the angle of incidence and angle of reflection correctly 95% of the time

Snell’s Law and refraction …determine the angle of incidence, angle of refraction, indices of refraction and material of mediums using snell’s law, correctly 90% of the time.

Total internal reflection

…determine the critical angle for two mediums correctly 90% of the time

© Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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Stage 2 – Assessment Evidence Students will demonstrate their learning/understanding in the following way(s):

Teacher-Created Assessments Pre-test: Students will take a 30 question pretest prior to initiating the unit on light. Post-test: Students will take the same exam as a post test to measure learning/understanding of content (Performance Assessments: ) HW Problems Power Point Project (Other Assessments: Peer, Self) Students will be required to hand in a rubric along with their Power point project that reflects how they think they did on the project. Categories on rubric will reflect actual grading procedure with a specific explanation of how to earn points for each category.

(Assessment Adaptations) All accommodations will be made for 504 and IEP’s that are required. Students will be paired heterogeneously according to ability for the power point project. Students will work closely with the teacher so progress is assessed often. The teacher will intervene and make adaptations where needed. Students will have access to computers throughout the entire project so spelling and grammar can be corrected.

© Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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Stage 3 – Learning Plan Learning Activities Instructional Strategies/Learning Activities: e.g., demonstration, discussion, small groups, role play, etc. Students will be paired and assigned a topic on light to create a power point to present to the class for review prior to the unit exam.

Introducing the lesson:

After the pre-test the teacher will begin the unit by using an exercise to get the students to explain what they know and think about light: The students have stumbled across a civilization that has no eyes. The civilization hears them discussing “seeing” and thinks it is some kind of black magic. They are holding the class captive and their only hope is to explain what light is. This is a good way to get the students involved in the content. Next the teacher explains the power point project that will be done by each group.

Instructional Sequence: (representing the content: teaching/learning activities, connecting to students’ prior knowledge, etc.)

Teacher activity (The teacher is doing….) 1 day:

Student activity (The student is doing…) 1 day:

Teacher engages students in an activity to bring about the prior knowledge and conceptions of the class on the topic of light.

The students are engaging in a discussion of how to explain light to someone that has no background knowledge of the topic.

The teacher Introduces the unit of Light. The power point project is explained first. The students are paired with partners first. The teacher explains that each student will be assigned a subtopic of light. The groups are responsible for creating a power point presentation of that sub topic to be presented in two weeks before the end of unit exam. The rubrics are passed out and explained. Each group is randomly assigned a subtopic of light. Students are encouraged to begin researching their

The groups should ask questions about the project.

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© Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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subtopic right away. The power point should review the main conceptual ideas discussed in class and real world applications and examples. 2nd day through 7th day: Introduction : Tell the students what ideas are to be discussed during the lesson. Ask the students a leading question. “What do we know about light?” Discuss with the students the ideas that they have. Lead them in the direction of how it travels. We want to arrive at the topic of the ray model of light. Talk about Newton and how he believed that light was a stream of fast moving, unimaginably tiny particles called corpuscles. Then speak of how light has been proven to have wave characteristics through experiment. Ray model of light: Light is represented as a ray that travels in a straight path. In this model, light can only change direction by an obstruction being placed in its path. The students have heard this idea before, so it should not have to be explained too thoroughly for them to understand it. This model was used as a way to study how light acts with objects whether it is particle or waves. This is called ray optics or geometric optics. Now ask the students where the rays of light come from that we see? Help them with ideas if needed. The rays come from sources of light. Everything that we see is a source of light whether it is luminous or illuminated. Talk about the two sources (luminous and illuminated) and give examples, the sun, a light bulb, fire, a book, pencil, etc… Explain why objects are visible. Is light emitting light from it or is light reflecting off of it? Briefly discuss: Opaque: where light is reflecting off of it but © Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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none is transmitted. (brick, book, wall) Transparent: media that transmit light. (air, water, glass) Translucent: media that transmit light but do not allow objects to be seen clearly. (lamp shades, frosted light bulbs) Speed of light: Pick an object in the room and discuss how the light has to travel a distance to the object or how light from the illuminated object has to travel a distance to be received by the eye. Discuss on a bigger scale how the light from the sun or moon has to travel a distance to get to the earth. Then bring up the formula for velocity and how we know the distance and if we can measure the time we can determine the velocity. But how can we measure the time? Talk of Michelson/Morely Michelson inferometer and ether. Michelson measured the time it took light to travel between two mountains in California 35 km apart. He used rotating mirrors to measure the small time intervals. His best result was (2.997996+0.00004) x 10^8 m/s. Diffraction: Turn of lights except for overhead or other source of light. Place an object in the path of the light and show the shadow. Notice that the edge of the shadow is not perfectly sharp. Why? This was done by Grimaldi. The shadow is wider than the actual object as it should be. Draw a diagram using rays of light and show how the light should travel in a straight line past the obstacle and create a sharp edge of a light/dark border. Look at the border of the shadow. It is actually bordered by colored bands. Talk about sound and this same phenomenon. Talk about what happens when an obstacle is placed in the path of sound. Now relate this to light. The same thing happens in light just on a much smaller scale. Use this to lead into Huygens’s principle. Huygens’s Principle: © Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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Each wave front can be thought of as a series of point sources of smaller waves. The wavelets expand in every direction and are in step with one another. The wavelets cancel each other out in all direction except for where they all move in the same direction. This is superposition. All of the wavelets add together to get a new wave front. When the new wave front passes through a barrier, all the wavelets recombine again to make a flat barrier except at the edges where it rounds off. No wave to cancel out roundness at edges. Draw a diagram of Huygens’s principle while discussing it. Use a compass to draw a wavelet, of the same radius, from several different points on a wave front. Color: Talk about light passing through a prism. Show with demonstration of light passing through prism projected onto the whiteboard. Newton did experiments on these colors produced by sunlight passing through the prism. He called these colors produced a spectrum. At first, Newton was using his corpuscle model of light explained that these colors were produced because the particles of light were hitting some unevenness or imperfection in the glass itself. He placed another prism in the path of the colored light expecting it to make the effect worse or spread the spectrum out even more. Instead in converted the spectrum back into white light. He concluded that white light was made up of the colors of the spectrum, and properties of the prism separated the light into the colors of the spectrum. Colors of the spectrum: ROYGBIV Based on the diffraction of Grimaldi and the Huygens’s principle, we know that light has wave properties. Visible light has wavelength from about 400nm to 700nm. Going from red (with the longest wavelength at 700nm) to violet (with the shortest at 400nm). Show spectrum. Talk about the other colors. © Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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Explain how the white light refracts or bends as it goes from air to glass to air. Each different wavelength in the white light bends at a different angle. This spreads out the white light into a spectrum. Colors by addition of light: Additive color process: Discuss how white light can be formed by other colors of light being added together. Tell the students that by using red green and blue you can make white light. Do demonstration using the light box. This is used in televisions and projectors (RGB). Use shadow arm in the light box to show how blocking different color lights creates different colors (yellow, cyan, magenta). Primary, Secondary and Complementary: Ask the students what the primary colors are. They will most likely say red, yellow and blue. This is what they are taught in art class. (Red and yellow make orange, yellow and blue make green, and red and blue make purple). Discuss how it is different for light. Red, Blue and Green are the primary colors for light because the produce white light. The primary colors can also be mixed to produce additional colors. Red and green make yellow, red and blue make magenta, and green and blue make cyan. The colors yellow, cyan and magenta are known as secondary colors because they are combinations of two primary colors. Look at the light box again. Notice that the yellow light and the blue light create white light. The green and magenta lights make white light. And the red and the cyan make white light. These colors are known as complementary colors if they make white together. Color by subtraction: Start a discussion on how light can be transmitted, reflected and absorbed. The color of an objected depends on what the color of the light is that is illuminating it and the wavelength of light absorbed and © Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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reflected by the object itself. The pigment or dyes in an object give it color. A dye is a molecule that absorbs certain wavelengths of light and reflects or transmits others. When light falls on an object, the wavelengths that are absorbed are turned into energy by the object, the wavelengths that are reflected or transmitted give the object the color. Give examples of different objects in the room. The difference between a dye and a pigment is that pigments usually are make of crushed minerals, rather than plant or insect extras. A pigment that absorbs only one primary color and reflects two from white light is a primary pigment (yellow, cyan and magenta). A pigment that absorbs two primary colors and reflects one color is called a secondary pigment (red, blue and green). Give examples. Notice that the primary pigment colors are the secondary light colors and the secondary pigment colors are the primary light colors. Mixing Pigments: Yellow and cyan make green Yellow and magenta make orange Magenta and cyan make purple Printers use magenta, yellow, and cyan to make images. Pigments are usually finely ground compounds such as titanium (IV) oxide (white), Chromium(III) oxide (green), and cadmium sulfide (yellow). Polarization: Ask the students if any of them have polarized sunglasses. If yes, ask them if they know what they do. If no, ask them the same question. What makes them so special compared to regular sunglasses. Ask if anyone has ever looked throught polariezed lenses (if nobody owns a pair of sunglasses). If yes, Ask them if they have ever rotated the glasses while looking through them. What happened? Light reflected off the road will get light and dark, some other sources of light will also get light and dark. The polarized lenses will block some forms of light in one position but will © Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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allow them to pass when rotated to other positions. Why? Polarization is the production of light in a single plane of oscillation. Give examples of a single plane. Begin a discussion involving the rope model. Get out the rope and create transverse waves with it. How can we block this wave. Use a barrier of some sort. Now create the wave perpendicular to its previous orientation but keep the barrier the same. Have the students notice how the wave is now able to pass through. Show the diagram of the rope model from the book (fig. 16-16). Polarized media are made up of long molecules in which electrons can oscillate all in the same direction. As light travels past the molecules, the electrons can absorb light waves that oscillate in the same direction as the electrons. This allows waves passing in one direction to pass while it blocks others. Waves vibrating parallel to the polarizing axis can pass. Light usually contains waves vibrating in all directions perpendicular to the direction of travel. 8th day: Students will begin to give their presentations using power point. After the presentation, students will hand in the rubric for their presentation. Adaptations to the Instructional Sequence to Differentiate: Discussion and Assessment of Learning: (Pointing out to students how what they are learning is related to the driving question; assessing students’ learning as a result of the lesson) Each presentation will be associated with a discussion following the presentation. Students will attempt to answer questions and lead discussion in the conceptions that relate to their subtopic. This will be carefully monitored by the teacher to assure correct information is being taught. Students will be graded according to the project rubric. The presentations are a review for the post exam. Closure: Extensions for early finishers:

Early finishers will join other groups to help them with ideas and to learn ideas for their presentation. They will be given a chance to go back and improve their project if © Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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necessary. Procedures: (already established procedures to be used and procedures to be taught for this lesson)

© Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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Lesson Development Resources Technology Tools and Materials: (classroom set-up, preparations, resources, etc.)

Projector Computers Power point (Contact Information) steve propheter [email protected]

© Gradel & Jabot 2009 (adapted from Jabot, Maheady, Rey 2005 (adapted from UbD, Wiggins & McTighe))

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