PROFESSIONAL DEVELOPMENT AP ® Physics 2 The Capacitor as a Bridge from Electrostatics to Circuits CURRICULUM MODULE For the redesigned course launching fall 2014 The College Board New York, NY Revised spring 2015 About the College Board The College Board is a mission-driven not-for-profit organization that connects students to college success and opportunity. Founded in 1900, the College Board was created to expand access to higher education. Today, the membership association is made up of over 6,000 of the world’s leading educational institutions and is dedicated to promoting excellence and equity in education. Each year, the College Board helps more than seven million students prepare for a successful transition to college through programs and services in college readiness and college success — including the SAT® and the Advanced Placement Program®.
The organization also serves the education community through research and advocacy on behalf of students, educators and schools. For further information, visit www. © 2015 The College Board. College Board, Advanced Placement Program, AP, AP Central, SAT, and the acorn logo are registered trademarks of the College Board.
All other products and services may be trademarks of their respective owners. Visit the College Board on the Web: www. Equity and Access Policy Statement The College Board strongly encourages educators to make equitable access a guiding principle for their AP programs by giving all willing and academically prepared students the opportunity to participate in AP. We encourage the elimination of barriers that restrict access to AP for students from ethnic, racial and socioeconomic groups that have been traditionally underserved.
Schools should make every effort to ensure their AP classes reflect the diversity of their student population. The College Board also believes that all students should have access to academically challenging course work before they enroll in AP classes, which can prepare them for AP success. It is only through a commitment to equitable preparation and access that true equity and excellence can be achieved. AP_Physics_2CM.indd 3 29/04/14 6:33 PM AP_Physics_2CM.indd 4 29/04/14 6:33 PM Contents Preface.
3 Connections to the Curriculum Framework. 3 Instructional Time and Strategies. 7 Activity 1: The Indicating Electrophorus. 15 Activity 1: Introducing the Capacitor.
18 Activity 2: Finding a Mathematical Model for Capacitance. 20 Activity 3: Extending the Model to Include Energy Storage. 25 Lesson 3: Capacitor Combinations. 29 Activity 1: Predicting Capacitor Combinations .31 Activity 2: Testing Predictions About Capacitor Combinations .32 Lesson 4: Capacitors in Circuits .37 AP_Physics_2CM.indd 5 29/04/14 6:33 PM Activity 1: Charging and Discharging Capacitor Behavior.
40 Activity 2: Collecting Graphs to Describe Capacitor Behavior. 42 Activity 3: Experimenting with Capacitors in a Parallel Circuit. 50 Handout 1: Capacitance Ranking Task. 51 Handout 3: Charge on a Capacitor .52 Handout 4: Energy Stored in a Capacitor.
54 Appendix A: Science Practices for AP Courses. 54 Appendix B: Table of Information and Equation Tables for AP Physics 2. 56 Authors and Reviewers. 58 AP_Physics_2CM.indd 6 29/04/14 6:33 PM Preface Preface AP® curriculum modules are exemplary instructional units composed of one or more lessons, all of which are focused on a particular curricular topic; each lesson is composed of one or more instructional activities.
Topics for curriculum modules are identified because they address one or both of the following needs: • A weaker area of student performance as evidenced by AP Exam subscores • Curricular topics that present specific instructional or learning challenges The components in a curriculum module should embody and describe or illustrate the plan/teach/assess/reflect/adjust paradigm: 1. Plan the lesson based on educational standards or objectives and considering typical student misconceptions about the topic or deficits in prior knowledge. Teach the lesson, which requires active teacher and student engagement in the instructional activities. Assess the lesson, using a method of formative assessment.
Reflect on the effect of the lesson on the desired student knowledge, skills, or abilities. Adjust the lesson as necessary to better address the desired student knowledge, skills, or abilities. Curriculum modules will provide AP teachers with the following tools to effectively engage students in the selected topic: • Enrichment of content knowledge regarding the topic • Pedagogical content knowledge that corresponds to the topic • Identification of prerequisite knowledge or skills for the topic • Explicit connections to AP learning objectives (found in the AP curriculum framework or the course description) • Cohesive example lessons, including instructional activities, student worksheets or handouts, and/or formative assessments • Guidance to address student misconceptions about the topic • Examples of student work and reflections on their performance The lessons in each module are intended to serve as instructional models, providing a framework that AP teachers can then apply to their own instructional planning. Note on Internet Resources All links to online resources were verified at the time of publication.
In cases where links are no longer working, we suggest that you try to find the resource by doing a key-word Internet search. — The College Board 1 AP_Physics_2CM.indd 1 29/04/14 6:33 PM AP_Physics_2CM.indd 2 29/04/14 6:33 PM Introduction Introduction This curriculum module presents AP Physics teachers with pedagogy and suggested inquiry activities for introducing students to capacitors and their behavior in circuits. This module consists of four inquiry-based lessons, each of which has several activities. The first lesson is an introduction to electrostatics.
The second lesson is about the design and function of parallel-plate capacitors. The third lesson gives students a chance to develop ideas about series and parallel capacitors in circuits. And the fourth lesson looks at the charging and discharging process for capacitors in a circuit with resistance. Together, these four lessons help develop students’ understanding of how energy is stored in circuits and how capacitors behave in circuits.
Connections to the Curriculum Framework This curriculum module builds upon student understanding of electric force, electric field, and potential. Students will extend their understanding of simple circuit models introduced in Physics 1 to include devices that can store separated charge and potential energy. This unit should precede a study of complex circuits with multiple elements (voltage sources, multiple resistors, and capacitors). Note that students will not need to apply Kirchhoff’s rules to solve simultaneous equations for circuit quantities, as in Physics C: Electricity and Magnetism.
Simple series and parallel resistor circuits are addressed in the Physics 1 curriculum. The Physics 2 curriculum framework includes capacitors in series and parallel circuits. After completion of the lessons in this module, students should have an understanding of: • The function of a capacitor • How capacitance is defined • How the dimensions and shape of a capacitor determine its capacitance • How capacitors in series and parallel arrangements behave • The steady-state behavior of capacitors in circuits containing both resistors and capacitors The following is a list of the enduring understandings and the associated learning objectives related to capacitor circuits in the Physics 2 curriculum framework. Appendix A Each learning objective in the curriculum framework is linked with one or more science practices that capture important aspects of the work that scientists engage in.
For a list of the AP Science Practices, see Appendix A or the curriculum framework in the AP Physics 1 and 2 Course and Exam Description. The science practices enable students to establish lines of evidence and use them to develop and refine testable explanations and predictions of natural phenomena. 3 AP_Physics_2CM.indd 3 29/04/14 6:33 PM AP Physics 2 Curriculum Module Enduring Understandings Learning Objectives 1.1 Instructional Time and Strategies This curriculum module consists of four lessons. The first lesson on electrostatics will take approximately one class period, depending on students’ level of prior knowledge.
This lesson introduces an intriguing device: the indicating electrophorus. Students develop a microscopic model for charge to explain its behavior. You may decide to precede this first activity with a basic investigation of electrostatics, involving frictional charging rods or sticky tape. The other three lessons each comprise two or more activities.
You should allow at least one class period (45–50 minutes) for the proper completion of each activity, with the possible exception of Lesson 3, Activity 1, which may take less time. • Lesson 1: Electrostatics ✱ Activity 1: The Indicating Electrophorus • Lesson 2: Capacitance ✱ Activity 1: Introducing the Capacitor ✱ Activity 2: Finding a Mathematical Model for Capacitance ✱ Activity 3: Extending the Model to Include Energy Storage • Lesson 3: Capacitor Combinations ✱ Activity 1: Predicting Capacitor Combinations ✱ Activity 2: Testing Predictions About Capacitor Combinations • Lesson 4: Capacitors in Circuits ✱ Activity 1: Charging and Discharging Capacitor Behavior ✱ Activity 2: Collecting Graphs to Describe Capacitor Behavior ✱ Activity 3: Experimenting with Capacitors in a Parallel Circuit The instructional strategies provided throughout this module incorporate a variety of guided inquiry-based activities for students. In several instances, students are introduced to a concept with a brief, engaging demonstration. You do not provide students with explanations for the behavior of the demonstration at this time.
After the demonstration, you facilitate as students in lab groups explore the materials themselves by collecting data and making observations along a sequence. You must decide how much guidance to give students; some 4 AP_Physics_2CM.indd 4 29/04/14 6:33 PM Introduction groups are capable of designing their own labs early in the course, while others will need more guidance at first. After small-group activities, students come together in a whole-class discussion to construct a model for what was observed. After the agreed-upon model is described, students move to other activities to extend the model.
You should decide what product to require from students after each lesson. Products may take the form of a writing assignment, a lab report, notes, or a graphic organizer. This inquiry-based instructional approach gives students more autonomy during investigations and they must think about or, if you direct, create essential questions. Students participate in the identification of variables and must predict the behavior of the system.
Where possible, allowing students to select aspects of the experimental method causes them to think about what can be measured and why. When students have participated in the process of designing the investigation, their analysis of the data takes on an aspect of “What did we find out?” rather than “Did we get the answer the teacher wants?” This approach, therefore, has the potential to evoke more critical thinking and reasoning about the concepts. Equation Tables Equations that students might use in solving problems or answering questions will be provided for them to use during all parts of the AP Physics 2 Exam. It is not Appendix B intended for students to memorize the equations, so you can feel comfortable in allowing them to use the AP Physics 2 equation tables on all activities and assessments.
For the AP Physics 2 equation tables, see Appendix B or the AP Physics 1 and 2 Course and Exam Description. 5 AP_Physics_2CM.indd 5 29/04/14 6:33 PM AP_Physics_2CM.indd 6 29/04/14 6:33 PM Lesson 1 Lesson 1: Electrostatics Guiding Questions • What are common properties of conductors and insulators? • How can an object be charged by frictional charging? • How can an object be charged by induction? • What are models of electrostatic interactions? Lesson Summary The observation and explanation of the electrophorus can be the basis of the explanation of many electrostatic phenomena including “static shocks,” lightning, grain elevator explosions, and gas station explosions. You can also use the Van de Graff generator. Using both an electroscope and an electrophorus, students will explore the processes of frictional charging, charging by induction/ polarization, and charging by conduction.
By the end of the activity students should be able to make predictions and claims about movement and distribution of charges. X Connections to the Curriculum Framework The learning objectives aligned to the topic of electrostatics are identified below: • Learning Objective (1.