Contents Brief Description How Can You Learn from Our Modular Approach? vii viii Session 1: Is the Climate Changing? Introduction 1 This session introduces the controversial issue of climate change. You will analyze data to determine if and how the climate is changing, learn about potential causes of climate change, and identify other information you will need to defend your opinion about global warming. Creating the Context 1 Exploration 1A: Is the Climate Changing? 2 Creating the Context 2 Gathering Information 2 Working with the Information 5 Making the Link 5 Exploration 1B: Why is the Temperature Rising? 6 Creating the Context 6 Gathering and Working with the Information 6 Making the Link 8 Exploration 1C: What s the connection between greenhouse gases and global temperature? 8 Creating the Context 8 Gathering and Working with Information 9 Making the Link 11 Looking Back 11 Session 2: What Is a Greenhouse Gas? Visible and Infrared Spectroscopy 13 You will use visible and infrared spectroscopy to investigate the absorption characteristics unique to greenhouse gases. A brief analysis of the nature of the electromagnetic spectrum and the interaction of light with matter will accompany the spectroscopic investigation. iii
Creating the Context 13 Gathering and Working with Information: 13 Working in Another Context: 15 Making the Link 16 Looking Back 18 Session 3: What Determines Whether a Gas Is a Greenhouse Gas? Lewis Structures and VSEPR, Polarity and Infrared Activity 19 You will be introduced to the nature of chemical bonding and molecular shape. You will also explore polarity and how molecular shape influences the absorption of infrared light. Creating the Context 19 Exploration 3A: How Are the Atoms in Greenhouse Gas Molecules Connected? 19 Creating the Context 19 Gathering and Working with Information 20 Exploration 3B: What Are the Shapes of the Greenhouse Gas Molecules? 21 Creating the Context 21 Gathering Information 21 Working with the Information 23 Working in Another Context 24 Exploration 3C: What Determines Whether a Gas Absorbs Infrared Radiation? 24 Creating the Context 24 Working with the Information 29 Working in Another Context 31 Making the Link 31 Looking Back 32 iv
Session 4: How Much Are Greenhouse Gas Concentrations Changing? Interpreting Graphs 33 You will graphically interpret the behavior of greenhouse gas concentrations as a function of time. Conversion between different units of measure will be necessary for comparison of the concentrations of different greenhouse gases. Creating the Context 33 Gathering Information: 33 Working with the Information: 35 Making the Link 36 Looking Back 39 Session 5: Why Are Greenhouse Gas Concentrations Rising? Chemical Equations 40 To understand why greenhouse gas concentrations are rising, we need to understand how these gases are created and destroyed. In this session, you will research the sources and sinks of the greenhouse gases and develop a qualitative understanding of why the concentrations are rising. In the process, you will develop skills in formulating and balancing chemical equations and in literature and world wide web research. Creating the Context 40 Exploration 5A: Is there CO 2 in your breath? 40 Creating the Context 40 Gathering Information 41 Working with the Information 41 Exploration 5B: What Are the Sources and Sinks of the Greenhouse Gases? 42 Creating the Context 42 Gathering Information 42 Exploration 5C: How Do We Balance the Relevant Equations? 43 Creating the Context 43 Working with the Information 43 Making the Link 45 Looking Back 46 v
Session 6: What Are Your Personal Contributions To Greenhouse Gas Emissions? Moles and Stoichiometry 47 You will use laboratory investigations and stoichiometric calculations to determine whether you personally are a significant source of greenhouse gases. You will examine your daily activities to estimate which ones have the greatest impact on greenhouse gas levels. For instance, are you responsible for more carbon dioxide emissions if you drive to Boston or fly? Balancing equations, mole calculations, stoichiometry, unit conversions, experimental design, and order of magnitude estimation are skills that will be developed during this session. Creating the Context 47 Exploration 6A: What Are Your Personal Contributions to CO 2 Emissions? 48 Creating the Context 48 Gathering Information 48 Working with the Information 49 Making the Link 50 Exploration 6B: Which Daily Activities Contribute to Rising 51 Greenhouse Gas Levels? Creating the Context 51 Working with the Information 51 Making the Link 54 Looking Back 54 Session 7: What Should We Do About Global Warming? Culminating Activity 55 In this culminating activity, you will be asked to conclude what we should do about global warming. This activity will require you to articulate what you have learned during the module and to support your conclusions with scientific and quantitative data. Your instructor will decide the format of this activity; papers, debates, posters and discussions are possibilities. Several options are given as examples so you can start to think about how you will respond. vi
Brief Description This module is driven by the question, Climate Change: What should we do about global warming? In striving to answer this controversial question, you will investigate properties of greenhouse gases and their potential link to global temperature changes. We emphasize an understanding of the chemical reactions that influence greenhouse gas concentrations, and in particular, determining which of our daily activities contribute significantly to rising greenhouse gas concentrations. Interdisciplinary Aspects. As you learn about the chemistry of global warming, you will also learn how it overlaps with other disciplines and areas of your life, including atmospheric chemistry, environmental science, and public policy. Level and Prerequisites. This module is designed to be covered in the first semester of a general chemistry course; no prerequisites are required. Chemistry Content Objectives. This module will ask you to develop a working knowledge of the following: Electromagnetic spectrum and spectroscopy: wavelength, frequency, and wavenumber, infrared spectroscopy, and visible spectroscopy. Chemical equations: formulating and balancing chemical equations. Stoichiometry: moles, molar mass, Avogadro s number, stoichiometric calculations, limiting reactant calculations. Lewis structures. VSEPR theory and molecular shape: dipole moments and polarity. Special topics, including the greenhouse effect, atmospheric composition, and global temperature trends. Scientific Skill Objectives. This module will also ask you to develop the following skills. Data Analysis (evaluating reliability of data, analysis of the impact of the results on society) Accessing Information (accessing current scientific data over the Internet, evaluating the reliability of information) Critical Thinking and Problem Solving (recognizing trends, using deduction, dealing with ambiguity, formulating questions) Communicating Results (oral, written, teamwork) vii
HOW CAN YOU LEARN FROM OUR MODULAR APPROACH? This guidebook includes inquiry-based activities for the classroom, for the laboratory, for the computer laboratory, and for homework. What do we mean by inquiry-based activities? Instead of giving you the answers and requiring you to memorize facts, we give you questions that will lead you toward a deeper understanding of chemistry concepts and approaches used by scientists in solving problems. The curriculum requires active participation from you, not only in the laboratories but also in the classroom. You will be recording observations from demonstrations, doing experiments, solving problems, discussing results, and constructing models to explain your observations and analyses. Organization of the Module The module begins with a question that provides a context for understanding and exploring chemistry concepts. Sessions. The module is divided into sessions, each beginning with a Session Question. Each session focuses on one aspect of the Module Question and will raise the issues you need to consider to respond to the Module Question. Creating the Context. This section states the goal of the Session and frames the Session Question. The text discusses why the question is important, reminds you of information discussed previously, gives background information, and describes what you can do to find out more. Explorations. Several Sessions have been divided into Explorations. Each Exploration begins with a question that considers the Session Question in more depth and in different ways. Your instructor will choose which Explorations to use depending on her or his goals and the needs of your class. Gathering the Information. This section describes how to gather the information that you will need to respond to the Session and Exploration Questions. Activities of the following types are used for this guided inquiry: a. Demonstrations will be performed by your instructor, shown on a video, or simulated on a computer. You ll need to understand the purpose of the experiment, make detailed observations, and attempt to explain these observations. viii
b. Small group discussion and class discussion will help you formulate responses to questions, gather data from other groups, and give you different perspectives. c. In a laboratory exploration, you will design and carry out experiments to respond to a specific question. These experiments will require you to use chemistry principles and thinking skills related to your work in the classroom. d. Computer assignments will ask you to use the computer to gather information. Working with the Information. The questions in this section are provided to help you explore the observations and data you have collected. Your instructor will choose which of these questions to use for interactive discussion, small group work, or homework. Working in Another Context. This section asks you to apply what you have learned to a problem in a new context. Making the Link. In this section, you will reflect on how your learning has helped you formulate a response to the Session (or Exploration) Question. Looking Back. Each Session ends with a section called Looking Back. The Looking Back provides you with a list of the chemistry concepts you have learned, indicated by bold type, and a list of problem-solving skills that are appropriate to put on a resume. Culminating Project. As the Module ends, you will be asked to do a project that will integrate everything you have learned. General Approach Learning in a Context. You may wonder about the necessity of a context for learning chemistry. You may feel that you could just learn the concepts and not bother learning all the contextual information. Research in cognitive science has shown, however, that we retain knowledge better when appropriate background material is available. We have built a context surrounding the chemistry concepts and the problemsolving skills that we hope you will learn in this module. We hope that this context will help you make links to your background knowledge and to experiences from your everyday life. We believe that making these connections will aid your comprehension and enhance your retention. Transforming Knowledge. As part of this module, you will also be encouraged to find solutions to problems that cannot be solved by simply telling knowledge. At this stage in your academic careers, you need to make the transition from simply telling facts you have memorized to transforming your knowledge to solve new problems. This is what scientists and professionals such as doctors do. They cannot be familiar with every case ix
or remember all the information they learned in their training. But if they have learned how to approach complex problems, they will be equipped to deal with cases for which they were trained. More importantly, they will be able to deal with new issues. Therefore, they must know how to approach complex problems. In this module, we hope to give you experience with approaches used by scientists to solve problems, especially those for which an answer is not immediately obvious and for which multiple solutions are possible. You will find that real-life problem solving is an iterative process. When you do not know how to solve a problem, you start by exploring your best ideas. If these ideas do not lead you toward a solution, you may have to back-track, rethink your ideas, and try something else. This process of generating and then refining your ideas allows you to define the problem more clearly. Eventually, you may reach an acceptable solution. As you generate and refine ideas about the issues and concepts in this module, your thinking will become more sophisticated, and your understanding will deepen. Enjoy! Sharon Anthony Jade Bender Tricia A. Ferrett July 2003 x