Unit One Organizer: Waves (Approximate Time 7 weeks)

Transcription

1 The following instructional plan is part of a GaDOE collection of Unit Frameworks, Performance Tasks, examples of Student Work, and Teacher Commentary. Many more GaDOE approved instructional plans are available by using the Search Standards feature located on GeorgiaStandards.Org. Unit One Organizer: Waves (Approximate Time 7 weeks) OVERVIEW: Studying the physics of waves is important because it provides a rich glimpse into the physical world which we seek to understand and describe. In addition, there are a variety of phenomena which resemble waves so closely that we can describe such phenomena as being wavelike. This unit focuses on developing a clear understanding about the properties of waves, and the applications of these properties to how lenses, microscopes, and telescopes work. Throughout the unit the students will have the opportunity to experience what researchers do as the students work on their own research project. The student s research project and the weekly readings of scientific articles will provide the necessary connections to make the study of physics relevant to the student s own experiences. Furthermore, this unit will provide the teacher with the opportunity to connect Newtonian physics to the modern understandings of the properties of waves and wave-particle duality. The lessons of this unit are built around laboratories that provide opportunities for the students to see and experience the phenomena discussed in class. The lessons are written to be student centered instead of teacher centered. Being student centered allows for a maximum of interaction between the students, as well as the students and the teacher. This approach allows the teacher the opportunity to recognize misconceptions and develop instruction guiding students towards modifying those misconceptions in a non-threatening environment. STANDARDS ADDRESSED IN THIS UNIT Focus Standard: SP4. Student will analyze the properties and applications of waves. a. Explain the processes that results in the production and energy transfer of electromagnetic waves. b. Experimentally determine the behavior of waves in various media in terms of reflection, refraction, and diffraction of waves. c. Explain the relationship between the phenomena of interference and the principle of superposition. d. Demonstrate the transfer of energy through different mediums by mechanical waves. e. Determine the location and nature of images formed by the reflection or refraction of light. October 2006 Page 1 of 16

2 Supporting content Standards SP3. Students will evaluate the forms and transformations of energy. a. Analyze, evaluate, and apply the principle of conservation of energy and measure the components of work-energy theorem by Describing total energy in a closed system. Identifying different types of potential energy. Calculating kinetic energy given mass and velocity. Relating transformations between potential and kinetic energy. b. Explain the relationship between matter and energy. SP5. Students will evaluate relationships between electrical and magnetic forces. a. Describe the transformation of mechanical energy into electrical energy and the transmission of electrical energy. SP6. The student will describe the corrections to Newtonian physics given by quantum mechanics and relativity when matter is very small, moving fast compared to the speed of light, or very large. a. Explain matter as a particle and as a wave. b. Describe the Uncertainty Principle. Characteristics of Science Standards SCSh1. Students will evaluate the importance of curiosity, honesty, openness, and skepticism in science. a. Exhibit the above traits in their own scientific activities. b. Recognize that different explanations often can be given for the same evidence. c. Explain that further understanding of scientific problems relies on the design and execution of new experiments which may reinforce or weaken opposing explanations. SCSh2. Students will use standard safety practices for all classroom laboratory and field investigations. a. Follow correct procedures for use of scientific apparatus. b. Demonstrate appropriate technique in all laboratory situations. c. Follow correct protocol for identifying and reporting safety problems and violations. October 2006 Page 2 of 16

3 SCSh3. Students will identify and investigate problems scientifically. a. Suggest reasonable hypotheses for identified problems. b. Develop procedures for solving scientific problems. c. Collect, organize and record appropriate data. d. Graphically compare and analyze data points and/or summary statistics. e. Develop reasonable conclusions based on data collected. f. Evaluate whether conclusions are reasonable by reviewing the process and checking against other available information. SCSh4. Students will use tools and instruments for observing, measuring, and manipulating scientific equipment and materials. a. Develop and use systematic procedures for recording and organizing information. b. Use technology to produce tables and graphs. c. Use technology to develop, test, and revise experimental or mathematical models. SCSh5. Students will demonstrate the computation and estimation skills necessary for analyzing data and developing reasonable scientific explanations. a. Trace the source on any large disparity between estimated and calculated answers to problems. b. Consider possible effects of measurement errors on calculations. c. Recognize the relationship between accuracy and precision. d. Express appropriate numbers of significant figures for calculated data, using scientific notation where appropriate. e. Solve scientific problems by substituting quantitative values, using dimensional analysis and/or simple algebraic formulas as appropriate. SCSh6. Students will communicate scientific investigations and information clearly. a. Write clear, coherent laboratory reports related to scientific investigations. b. Write clear, coherent accounts of current scientific issues, including possible alternative interpretations of the data c. Use data as evidence to support scientific arguments and claims in written or oral presentations. d. Participate in group discussions of scientific investigation and current scientific issues. The Nature of Science Standards SCSh7. Students will analyze how scientific knowledge is developed. a. The universe is a vast single system in which the basic principles are the same everywhere. b. Universal principles are discovered through observation and experimental verification. October 2006 Page 3 of 16

4 c. From time to time, major shifts occur in the scientific view of how the world works. More often, however, the changes that take place in the body of scientific knowledge are small modifications of prior knowledge. Major shifts in scientific views typically occur after the observation of a new phenomenon or an insightful interpretation of existing data by an individual or research group. d. Hypotheses often cause scientists to develop new experiments that produce additional data. e. Testing, revising, and occasionally rejecting new and old theories never ends. SCSh8. Students will understand important features of the process of scientific inquiry. Students will apply the following to inquiry learning practices: a. Scientific investigators control the conditions of their experiments in order to produce valuable data. b. Scientific researchers are expected to critically assess the quality of data including possible sources of bias in their investigations hypotheses, observations, data analyses, and interpretations. c. Scientists use practices such as peer review and publication to reinforce the integrity of scientific activity and reporting. d. The merit of a new theory is judged by how well scientific data are explained by the new theory. e. The ultimate goal of science is to develop an understanding of the natural universe which is free of biases. f. Science disciplines and traditions differ from one another in what is studied, techniques used, and outcomes sought. Reading Standard Students will enhance reading in all curriculum areas by: a. Reading in all curriculum areas Read technical texts related to various subject areas. c. Building vocabulary knowledge Demonstrate an understanding of contextual vocabulary in various subjects. Use content vocabulary in writing and speaking. Explore understanding of new words found in subject area texts. d. Establishing context Explore life experiences related to subject area content. Determine strategies for finding content and contextual meaning for unknown words. October 2006 Page 4 of 16

5 ENDURING UNDERSTANDINGS 1. Electromagnetic waves are produced by changing the motion of charges or by changing magnetic fields. 2. The energy of electromagnetic waves is transferred to matter in quantized quantities. 3. The energy content of electromagnetic waves is directly proportional to the frequency of electromagnetic waves. 4. Light waves are transverse. 5. Light slows down, bends toward the normal and has a shorter wavelength when it enters a medium with a higher index of refraction than the medium in which it was previously traveling. 6. Blue light has more energy (a shorter wavelength and higher frequency) than red light. 7. The energy of a wave falls off as the wave moves away from its source. 8. Diffraction takes place when the wavelength of a wave and the size of an obstacle or opening are comparable. 9. Sound waves are longitudinal, mechanical waves. 10. The amplitude of mechanical waves determines the energy of mechanical waves. 11. Interference occurs when two waves simultaneously arrive to a particular point in space. If the phase difference of the two waves is 0º or a whole number of wavelengths, then the waves produce constructive interference. If the phase difference of the two waves is 180º, then the two waves cancel each other. A phase difference between the two waves that is not 0 or 180º will cause partially destructive interference. 12. At the interface of a medium, light can be reflected or refracted. 13. The Doppler Effect is caused by the relative motion between the wave source and the observer. 14. Transverse waves cause particles to vibrate back and forth, perpendicular to the wave direction. 15. Lenses and mirrors form images. Different combinations of lenses and mirrors may form real or virtual images. 16. A photon is a unit of light. 17. Large objects have very short wavelengths when moving and thus cannot be observed behaving as a wave (DeBroglie Principle). 18. Increasing light intensity on a material increases the number of emitted electrons but not the kinetic energy of the electrons. (the photoelectric effect). October 2006 Page 5 of 16

6 ESSENTIAL QUESTIONS: One Stop Shop For Educators 1. Why do we see different colors? 2. Why, when looking at objects through a glass, do they look like they are bent? 3. How does energy moves through space? 4. How do tsunami and earthquake waves transfer energy? 5. Why do you get sun burned even in a cloudy day? 6. Why does the pitch of a siren change depending if the source of the siren moves towards us or away from us? 7. Why are the colors in a rainbow (primary) always in the same order? 8. Why can mirrors form distorted images? 9. How do lenses work? 10. Why do we sometimes hear an echo? 11. Why do mirrors on the passenger side of the car say Objects may be closer than they appear? CONCEPTS: Electromagnetic waves, particle-wave duality, energy transfer, reflection, refraction, diffraction, interference, principle of superposition, mechanical waves, longitudinal waves, transverse waves, light, energy, uncertainty principle, virtual image, real image. LANGUAGE: Energy, waves, electromagnetic wave, electromagnetic spectrum, X-ray, Gamma ray, radio waves, infrared, visible, ultraviolet, reflection, refraction, diffraction, constructive interference, destructive interference, transverse waves, longitudinal waves, image, focus, object, image distance, object distance, magnification, inverted image, real image, virtual image, Doppler effect, pitch, intensity, amplitude, frequency, sound waves, prism, color, superposition principle, crest, trough, significant figures, calculate, experiment, precision, measure, accuracy, SI units, describe, scientific notation, conclusion, hypothesis, data, contrast, compare, variable, infer, analyze, predict, interpret, percent difference. October 2006 Page 6 of 16

7 MISCONCEPTIONS AND PROPER CONCEPTIONS One Stop Shop For Educators MISCONCEPTIONS Waves transport matter. There must be a medium for a wave to travel through. Waves do not have energy. All waves travel the same way. Frequency is connected to loudness for all amplitudes. Big waves travel faster than small waves in the same direction. Different colors of light are different types of waves. Pitch is related to intensity. Light is a particle. Light is a mixture of particles and waves. Light waves and radio waves are not the same thing. The speed of light never changes. PROPER CONCEPTIONS Waves transport energy; not matter. Only mechanical waves need a medium in order to propagate. Electromagnetic waves do not need a medium in order to propagate. Waves are an energy transport phenomena that transport energy along a medium without transporting matter. Based on the direction of movement the individual particles of the medium travel relative to the direction in which a wave travels, a wave can be categorized in to one of three wave groups: longitudinal, transverse or surface. Frequency refers to how often the particles of a medium vibrate within a unit of time when a wave passes through the medium. The loudness of a sound relates to the amplitude of the wave. All electromagnetic waves in vacuum travel at the speed of light. The speed of all mechanical waves depends of the mechanical properties of the medium. Light is a form of electromagnetic wave. Colors are the result of the differences in energy of electromagnetic waves that fall in the visual part of the electromagnetic spectrum. The pitch of a sound is related to its frequency. Light is a form of electromagnetic radiation. It shows both wave and particle properties depending on the type of experimental conditions under which light is being studied. Light exhibit characteristics of both waves and particles. Radio waves are light waves, or electromagnetic waves. Visible light waves have a shorter wavelength than radio waves. The speed of light changes when light enters a denser medium by a factor called the index of refraction of the medium. October 2006 Page 7 of 16

8 MISCONCEPTIONS AND PROPER CONCEPTIONS (continuation) MISCONCEPTIONS The addition of all colors of light yields black. In refraction, the frequency of light changes. Refraction is the bending of waves. A mass moving at the speed of light becomes energy. Light is one or the other a particle or a wave only. Particles cannot have wave properties. The position of a particle always can be exactly known. Photons of higher frequency are bigger than photons of lower frequency. PROPER CONCEPTIONS The addition of all colors of light produces a white light. Adding different colors of paint might produce a dark color of paint. When a ray of light is refracted its frequency stays the same but the wavelength and velocity will change. Refraction results from the change in direction of a wave due to a change in its velocity as it moves from one medium to another with a different index or refraction. Waves do not bend. Refraction results from the change in direction of a wave due to a change in its velocity as it moves from one medium with an index of refraction to another medium with a different index of refraction. The mass of an object increases with velocity. The relativistic expression is mo m = 2 v 1 c Light is an electromagnetic wave. Depending on the experiment it may show either properties of a wave or properties of a particle. The wave-particle duality of objects is always present. The wavelength of an object is inversely proportional to its momentum. The position of a particle can be know only up to a limit given by the Uncertainty Principle Δx Δp h A photon is the corpuscular description of light. A photon does not have mass or volume. Photons have momentum and energy only. Higher frequency photons will have more energy and a shorter wavelength than photons of lower frequency. 2 October 2006 Page 8 of 16

9 EVIDENCE OF LEARNING: By the conclusion of this unit, students should be able to demonstrate the following competencies: Culminating Activity: Student Research Project Objective: The objective of this culminating task is to connect the physics concepts presented throughout this unit with real life applications. To accomplish this, the student will complete a research project in which he/she will build an instrument that can be used to measure a physical variable. Furthermore, it is also expected that the student will prepare an oral presentation with visual aids and write a final report of his/her experiment. Both will emphasize connections between what he/she did and physical concepts studied. The Task: The teacher should provide a schedule for completing the project. Before beginning the project the teacher and the students should develop a Research Project Rubric (a suggested list of items to include in the rubric) and go over the graphic organizer for experimental inquiry (see below). A suggested Project Check List for the project is also given. The Resources: Below you will find a list of bibliography sources that could provide some research ideas. However, it is recommended that the students come up with their own ideas. 1. Carlson, Shawn; Caught in a Wind Tunnel. The Amateur Scientist, Scientific American. November 1997 p Carlson, Shawn; Detecting Natural Electromagnetic Waves. The Amateur Scientist, Scientific American. May 1996; p Carlson, Shawn; The New Backyard Seismology. The Amateur Scientist, Scientific American. April 1996 p 100. Sequence Instruction and Learning Below there is a suggested sequence to guide students through the completion of this project. It is important to set the stage for the work to be done from the first week. It is recommended that during the extension of the unit the students are given two days to work in class. Research Project (week one) Explain to the students the objectives of the research project. Provide them with a calendar of deadlines for completion of different parts of the project and help them develop the rubric to assess the project. See suggested items to include in the rubrics. Research Project Classroom Working Day 1 (around the third week of the unit) Students will submit their first progress report on their project this day. Share with the students the Research Project Classroom Working Day Rubric and instruct them to work individually on their own projects. The teacher should conduct individual or group conferences with the students while they work on their projects. The students must use the classroom time to work on their experiment, seek advice from the teacher or classmates about problems with their experiment, and collaborate with other students to improve their projects. Before leaving for the day the students must write a report of their day s experience. The report should include feedback received, modifications that resulted from their discussion with other students or the teacher, and next steps in the process of designing their experiment. October 2006 Page 9 of 16

10 EVIDENCE OF LEARNING (continuation): Research Project Classroom Working Day 2 (around the fifth week of the unit) Students will submit their second progress report on their project this day. The teacher should conduct individual or group conferences with the students while they work on their projects. At this point, as a minimum, the students should have built their device and taken some preliminary data with it. The students must use the classroom time to work with their data, seek advice from the teacher or classmates about problems with their experiment, and collaborate with other students in ideas on how to improve their projects. Before leaving for the day the students must write a report of their day s experience. The report should include feedback received, modifications that resulted from their discussion with other students or the teacher, and next steps in the process of designing their experiment. Classroom Presentations (last week of the unit) Students will present their research project to the class. Each student s presentation must be seven minutes or less. October 2006 Page 10 of 16

11 EVIDENCE OF LEARNING (continuation): Project Title: Below Expectations Meets Expectations Exceeds Expectations Project Check List Student Name: Project Topic *The topic lends itself to experimentation, rather than demonstration *The topic is unique or innovative, shows creativity *The question is sufficiently limited to allow investigation Experimental Design *The project shows originality in its design and procedure (based on the student s age and experience). *The project reflects appropriate investigative techniques. *Variables to be investigated are clearly identified. *Attention is given to controlling other possible variables. *The project shows imaginative use of available materials. *Data collected includes both written observations and numeric measurements (where appropriate). *Repeated trials or multiple subjects are included in the procedure. Exhibit Display *The exhibit contains the following information: Project title, Experimental Question, Student Hypothesis, Identification of Variables, Description of Procedures, Data Collected, Summary of Results, Student s conclusion *Sufficient data were collected to allow conclusions to be made. *Exhibit is visually appealing; shows evidence of being the student s own work; information in the exhibit is recorded neatly and accurately *Tables, graphs, etc., are used to show results (where appropriate). *Exhibit is helpful in communicating the ideas/results of project. Student Discussion *The student s discussion indicates sound understanding of what was done in the experiment, as well as the ability to manipulate the equipment used (if any). *The student summarizes the results and discusses conclusions regarding the experiment. *Conclusions reached are justified, based on the experimental data. *The student identifies new questions for investigation, based on this experiment. October 2006 Page 11 of 16

12 EVIDENCE OF LEARNING (continuation): Graphic Organizer for Experimental Inquiry Observation Relevant Theory/Rule Relevant Theory/Rule Relevant Theory/Rule Relevant Theory/Rule Possible Explanation Prediction Experiment Results October 2006 Page 12 of 16

13 EVIDENCE OF LEARNING (continuation): Induction Deduction Abstraction Suggested Items to include in the Rubric Category Descriptors Expectation Identifies elements (specific pieces of information or observations) from which to make inductions. Interprets the information from which inductions are made. Makes and articulates accurate conclusions (inductions) from the selected information or observations. Identifies and articulates a deduction base on important and useful generalizations or principles implicit in the information. Accurately interprets the generalizations or principles. Identifies and articulates logical consequences implied by the identified generalizations or principles. Identifies a representative general or abstract pattern for the situation or information. Clearly and accurately identifies all relevant information from which to make inductions. The type of information selected reflects creative insight and a careful analysis of the situation Provides accurate interpretations that illustrate insight into the information from which they were made. The interpretations reflect a study of or a familiarity with the particulars of the topic. Draws conclusions that reflect clear and logical links between the information or observations and the interpretations made from them. The rationale for the interpretations shows a thoughtful and accurate attention to the process of induction. Selects generalizations or principles that show extreme insight into the topic. Demonstrates an understanding of the generalizations or principles that is not only accurate but provides a unique perspective on the topic. Accurately identifies logical conclusions implied by the generalizations or principles. Recognizes more subtle inferences that could have important effects on the subject area. Identifies a general or abstract pattern that provides unusual or provocative insights into the information under study. The pattern furnishes the means for seeing other material from a unique perspective. October 2006 Page 13 of 16

14 EVIDENCE OF LEARNING (continuation): One Stop Shop For Educators Suggested Items to include in the Rubric (continuation) Category Descriptors Expectation Investigation Problem Solving Experimental Inquiry Accurately identifies what is already known or agreed upon about the concept, the past event, or the future event. Develops and defends a logical and plausible resolution to the confusions, uncertainties, or contradictions about the concept, the past event, or the future event. Identifies viable and important alternatives for overcoming constraints or obstacles. Selects and adequately tries out alternatives. If other alternatives were tried, accurately articulates and supports the reasoning behind the order of their selection and the extent to which each overcame the obstacles or constraints. Accurately explains the phenomenon initially observed using appropriate and accepted facts, concepts, or principles. Presents a thorough and correct account of what is already known. Supplies information that may not be commonly known, but that has some bearing on the topic being studied. Provides a logical and well-developed resolution to the confusions, uncertainties, or contradictions. The resolution reflects creative thinking as well as thoughtful attention to the details of the problem. Identifies creative but plausible solutions to the problem under consideration. The solutions address the central difficulties posed by the constraint or obstacle. Engages in effective, valid, and exhaustive trials of the selected alternatives. Trials go beyond those required to solve the problem and show a commitment to an in-depth understanding of the problem. Provides a clear, comprehensive summary of the reasoning that led to the selection of secondary solutions. The description includes a review of the decisions that produce the order of selection and how each alternative fared as a solution. Provides an accurate explanation of the phenomenon. The facts, concepts, or principles used for the explanation are appropriate to the phenomenon and accurately applied. The explanation reflects thorough and careful research or understanding. October 2006 Page 14 of 16

15 Suggested Items to include in the Rubric (continuation) Category Descriptors Expectation Experimental Inquiry Makes a logical prediction based on the facts, concepts, or principles underlying the explanation. Sets up and carries out an activity or experiment that effectively tests the prediction. Effectively evaluates the outcome of the activity or experiment in terms of the original explanation. TASKS Makes a verifiable prediction that reflects insight into the character of the phenomenon. The prediction is entirely appropriate to the facts, concepts, or principles used to explain the phenomenon. Sets up and carries out an experiment that is a complete and valid test of the prediction and addresses all important questions raised by the prediction. The activity or experiment is designed to provide complete and accurate data and a model of the experimental design. Provides a complete and accurate explanation of the outcome of the activity or experiment and does so in terms of the relevant facts, concepts, or principles. Provides insights into the nature of the phenomenon studied or the facts, concepts, and principles used to explain it. The collection of the following tasks represents the level of depth, rigor and complexity expected of all students to demonstrate evidence of learning. Task: Description: Discussion, Suggestions for use: Possible Solution : October 2006 Page 15 of 16

16 SAMPLE OF STUDENT WORK October 2006 Page 16 of 16