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Developing Energy Conception of Students in Chemistry Class: Research on the learning and teaching of energy by BNU Group Wang Lei Wang Weizhen Wei Rui Jing Zhiying Jiang Tao Meng Qingrui Chemistry College of Beijing Normal University [email protected] Introduction In the framework for K-12 science education, energy, one of the core ideas, is also discussed as a crosscutting concept. Besides the definitions of energy at both the macroscopic and microscopic scales, energy transfer and conservation, as well as the relationship between energy and forces are focused on as the main questions in energy learning. In chemistry education, besides matter, energy is another major theme in chemistry learning. Energy is a word that is used so much in school that there are many misconceptions about it. Students consider energy as a concept related to life, health and food (Black &Solomon, 1983). Not only primary school students, but also some high school students still think energy is immeasurable (Solomon, 1985; Watt, 1983). Researchers found that when students say energy is conserved, they mean energy is stored in a system, and can be released in an initial form (Brook& Driver, 1984; Kesidou & Duit, 1993; Solomon, 1985). Survey research also shows that endothermic reactions are not thought to be spontaneous, and that students consider outside conditions on a spontaneous judgment basis, like heating, rather than Gibbs free energy (Gabriela, Ribeiro, Pereira Ma, 1990; Boo, 1998). Teachers also lack an overall understanding of energy and how to teach important ideas about energy. Although they are familiar with the content, the importance of teaching energy, and what is the most difficult for students to learn, teachers need to more information covering many aspects regarding the teaching of energy. Based on research literature on the learning and teaching of energy, we focus on the following questions: Is energy teachable and learnable for various students? What energy ideas should be taught at the various grade levels? How do we teach energy concepts? In the first part of the paper, we introduce the general framework of our research, including the content about energy in the high school science curriculum of Mainland China, and considerations about the basic structure of students’ epistemic systems. Then, we review research from our group research the teaching and learning about energy. We conclude this paper by discussing implications of our research. General framework 1. The content about energy in the high school chemistry curriculum Energy is major component of the high school’s chemistry curriculum. Much of the curriculum focuses on reactions and energy with less attention to the relationship between the structure of substance and its properties and energy. In Mainland China, from the curriculum reform in 2001, building the energy conception in chemistry learning has become a focus of reform. In high school, students learn knowledge about energy presented in Table.1. The curriculum includes the following ideas: the energy in reactions, atomic structure and chemical bonding, thermochemistry, and electrochemistry. 1 Table.1 Items about energy of high school curriculum standard in Mainland China Theme Items in high school curriculum standard Junior High School Chemical change: basic characteristics Chemistry & social development: chemistry & energy 1. Know about energy change in chemical reactions, 2. Realize the importance of gaining energy from reactions. 1. Know the importance of complete combustion, 2. Describe the influence to the environment when using fuels like hydrogen, biogas, utilization petroleum gas, alcohol, gasoline and coal, identify the least pollution fuel. 3. Explain the significance of fossil fuel, 4. Know the rich resources in sea. Senior High School- compulsory stage Chemistry reactions & energy 1.Use chemical bonding to explain the reason of energy change in reactions 2.Describe the examples of transformation between chemical energy and thermal energy in daily live. 3.State the transformation between chemical energy and electric energy and application in life by giving an example. 4.Identify the importance of raising combustion efficiency, developing clean energy, and new fuel cells. Junior High School- selective stage Module theme: Material structure & properties Atom structure & 1. Identify ionization energy and electronegativity, Element properties 2. Use ionization energy to explain the element properties. Chemical bonding& material properties 3. 1. Know extra nuclear electrons transition and the application. Know the application of lattice energy, and use the value to predict the strength of ionic bond. Module theme: Chemical reaction principle 1. Explain the energy changes in reactions and transformations in energy states. Chemistry reactions 2. Collect information to explain how energy is important to humans, including & energy describing the significance of chemistry in solving fuel problems. 3. State the transformation between chemical energy and thermal energy, 4. Explain heat of reactions, Enthalpy change, and calculate energy changes using Hess’ law. 5. Use an inquiry process to understand the transformation between chemical energy and electric energy, a. Explain the principle of cells, b. Write equation of electrode reactions and cell reactions. c. Collect information online to know categories and principles of electrochemical cells, d. Evaluate the application of the transformation between chemical and electric energy. 6. Explain metal corrosion and investigate preventive measures. 2 Reaction rate & chemical equilibrium 1. 2. 3. 4. 2.Identify activation energy and its influence on reaction rate. Predict the direction of reaction through the value of enthalpy change and entropy change. Describe the process of chemical equilibrium and apply K to calculate conversion ratio Conduct an inquiry to determine the influence of temperature, concentration, and pressure to chemical equilibrium,and explain the result. In Mainland China, energy has received more attention since the curriculum reform. The change can be seen not only from the number of items in the curriculum standards, but in the energy themes that are covered. In selective stages of senior high school, the section in Table 1 named “Chemistry reactions & energy”, which includes the knowledge of thermochemistry and electrochemistry, is organized according to the energy conversion (transformation), for example between chemical energy and heat energy, and between chemical energy and electric energy . However, because there are not so obvious energy clues in other parts of standard chemistry curriculum, the energy view is sometimes ignored in teaching. Another problem is the knowledge of energy is still valued more than the ability to analyze issues from an energy perspective. Chemistry focuses only on some of the ideas in energy construct. In chemistry, energy is discussed mainly in two dimensions (Figure 1). Figure 1. Two dimensions of energy in high school chemistry First, what is energy? It can be explained both at the macro- and microscopic levels, but in senior high school, the emphasis is on the microscopic (See Figure 2). Figure 2. What energy ideas are discussed in chemistry 3 An atom is the smallest indivisible particle of matter. It is the basis of matter and reactions. The energy inside an atom is the total energy related to chemical reactions. But the energy inside atomic nucleus (nuclear energy) is just involved in nuclear reactions, which is different from chemical reactions. As a result, the energy outside the atomic nucleus is the one discussed in chemistry. We don’t mean that the kinetic and potential energy just belongs to the atomic nucleus and electrons themselves. All of this constitutes total energy of an atom, which with the energy of other atoms, as well as attraction potential energy caused by nuclear attraction and repulsive potential caused by repulsive force from other electrons, constitute total energy of a polyatomic molecule and make up the energy of matter. Second is energy transfer and transformation. The transformation between chemical energy and thermal energy (heat energy), also chemical energy and electric energy are the focal point of energy learning in high school. 2. The epistemic model of energy Energy conception is an overall understanding of energy. It is not only learning knowledge, but building the energy epistemic model. We believe that there is an interior factor which influences specific concept learning and a student’s cognition about specific topics. The factor is a kind of thinking model or perspective which is used in conceptual understanding and problem solving. We call it an “epistemic model”. We recognize that it is related with “epistemic field” based on specific field of subject, and there are three core construction elements as “epistemic perspective”, “epistemic path” and “ thinking style ”. We found that there are strong relationships between the progression of epistemic model and the learning of core concept (knowledge). To raise a theoretical model, we focus on two questions in our research: (1) what knowledge and core concepts are the key points of learning to build the epistemic model. (2) How many kinds of epistemic results (performances) occur, and what are they? In response, we built a theoretical epistemic model of energy, which consist of four parts: epistemic field, epistemic perspective, epistemic category (thinking style), and epistemic results (performance). Epistemic field is the 4 chemistry content we focus on. The wide-depth of the field is changeable. For instance, when we put emphasis on the whole of energy, it is an epistemic field, and we could study it as a whole to figure out corresponding perspectives and category of thinking style. But when we narrow down the range of study, we may consider energy transformation of the reaction system as an epistemic field. In a certain epistemic field, the relationship of epistemic perspectives, category of thinking style and results (performance) can be seen from Figure 3. Figure 3. In a specific epistemic field, the structure of epistemic model Epistemic results are the external performance. Some verbs like describe/explain/predict/design usually are used to show different levels of students epistemic performance. Epistemic perspectives are the internal basic cause of the results and performance, and are different with different cognition content and epistemic fields. Epistemic style categories are generally classified with macroscopic or microscopic, qualitative or quantitative, unsystematic or systematic, and stable or dynamic. Combined with the above epistemic factors is a description of the learning progression level students reach in certain fields. For example, Figure 4 shows us the ideal (expected) epistemic model when students face the epistemic field of “the factors which influence energy change of a system’’. “Reaction heat” and “△H of system” are the first level of epistemic perspectives. We can also identify them as the sub-epistemic field of “the factors which influence energy change of a system”. Macroscopic and microscopic reasons of a system are epistemic perspectives. When students use chemical bonds to examine the concept, this indicates reaching a microscopic level of learning. We also use verbs like describe/explain/design to show different levels of epistemic results and performance. Different epistemic perspectives lead to an epistemic category differential and various epistemic results. In order for students to build a conception of energy, the key point of research is to find out what are the epistemic perspectives behind multiple performances. These perspectives are the focal points in teaching and learning. The model is also a framework for evaluating textbooks and designing attainment tests. Under this general framework, we carried out the research on energy teaching and learning. Our research aim is to find out the epistemic perspectives that help students build energy conception in a specific context. Teaching and learning research on thermochemistry Many present surveys of teachers and students in both high schools and universities show students’ misconceptions in learning concepts related to thermochemistry. We can divide them into four kinds: (1) misconceptions about energy changes in reactions. Students usually confuse 5 macroscopic and microscopic energy concepts. For example when explaining the relationship between energy change and chemical bonds, students may agree that bonds forming require energy and bonds breaking release energy. (2) Regarding thermal effects, it is a typical misconception that endothermic reactions must be heated to react. When assessing the thermal effects of reactions, students may judge it on reaction conditions (Yuan Guoqiang, 1989). (3) About the unit: kJ﹒mol-1. For instance, the reaction 2CO(g)+O2(g)=2CO2(g); △H=-566 kJ• mol-1, the value -566 kJ•mol-1means heat effect of per mole reaction, that is 2 mole carbon monoxide reacts with 1 mole oxygen to form 2 mole carbon dioxide. It doesn’t mean 1 mole carbon monoxide reacts to oxygen is able to produce 566kJ heat. Some supplementary materials using the unit kJ replace kJ﹒mol-1 by mistake. This leads to difficulties in understanding the concepts (Sheng Guoding, 2003; Li Wenfang, 2003). (4) About enthalpy and enthalpy change: enthalpy is often described as the heat capacity of the system by university students (Beall, 1994). It is difficult for most freshmen to distinguish enthalpy from heat or energy (Carson & Watson, 1999). Content knowledge is one important perspective for energy research. We examine how ideas of thermochemistry were development, how basic problems were discussed and how different ways of thinking were presented in different textbooks and monographs to find out the core content and knowledge shared among them. To understanding energy change of reactions, it is necessary to know both the manifestation and reasons causing the energy change. Seen from the heat of reaction perspective, energy change between a system and its surroundings, energy change of reactions is caused by forming and breaking chemical bonds; seen from the enthalpy change perspective, the change of system elements and thermodynamic states leads to energy change. Heat of reaction and enthalpy change are the two core epistemic fields in learning energy change of reactions (See Figure 4). Figure 4. Epistemic model of energy change of system 6 Heats of reaction and ΔH of system are the main parts of thermochemistry in high school. In order to obtain a functional epistemic model to guide teaching and learning, sub- models of heat of reaction and ΔH of system should be further built. a) Sub-model of heat of reaction In this model, heat of reaction is considered as epistemic object and it can be structured by three epistemic perspectives. Different perspectives show specific epistemic categories and levels and can be seen from the epistemic results/performance (Table 2). Table 2. Epistemic detailed model of heat of reaction Sub-perspecti Field Perspective Category /level Results /performance ve Heat of Microscopic Reaction Microscopic- Know bond type variation phenomenon, know reasons of qualitative- about some transition bond types, and understand system explain bond types of reactants and products influence energy Bond type energy changes. 7 changes microscopic- Explain energy changes using bond energy that is qualitative- energy required in chemical bonds breaking is not explain equal to energy produced in a bonds forming. Microscopic- Describe different expressions of bond energy, quantitative – calculate: enthalpy change by values of bond explain enthalpy: ΔrHm=ΣB.E.reactant-ΣB.E.product. Macroscopic-- Calculate heat of quantitative – calorimetric test, identify the importance of reaction explain temperature changes in measure. Measure Macroscopic-- Describe the importance of controlling reaction instrument quantitative – conditions, choose suitable calorimeter for a certain design condition. Measure of Bond energy Q=ΔT·C heat of reaction by Q=ΔT·C in Application Syst Endot Quantitative – Compare of reaction em hermi design produced in different reactions, design and revise heat c energy conservation and the heat the course of production. Exoth Quantitative – Calculate the heat that should be removed to ermic regulate maintain the temperature for reaction control. Sur- Suppl Quantitative – Select reactions to reduce the temperature of roun y heat design surroundings. ding Get Quantitative – Design reaction course to increase the burning rate heat design of fuels and use energy more scientifically. In the epistemic field of reaction heat, the relationship of epistemic perspectives can be easily seen in Figure 5. Figure 5. The relationship of the epistemic perspectives in reaction heat 8 b) Sub-model of ΔH of system In this model, ΔH of system is considered as epistemic field and it can be structured by three epistemic perspectives (Table 3). And the relationship of these epistemic perspectives is shown in Figure 6. Table 3. Epistemic detailed model of ΔH of system Category Field Perspective Results /performance /level ΔH system of ΔH of one Thermochemical Quantitative equation -describe Write thermochemical equation correctly (including states and temperatures) to express reaction heat, know the meaning of ΔH. reaction Quantitative Explain how ΔH change when the coefficient in equation changes. -explain ΔH=ΣH(product Quantitative Understand enthalpy is an expression of system energy, calculate enthalpy -explain change by ΔH=ΣH(products)—ΣH(reactants) s)—ΣH(reactants ) Explain the system energy changes using enthalpy change. 9 Influen Tempe Qualitative- ce rature describe factors Phase Semi-quanti Describe the relationship between matter states and ΔrH. Understand the tative-descri importance of marking matter states in thermochemical equation. to ΔH State the relationship between enthalpy change and temperature be Solven Qualitative- Describe solvent influence the value of enthalpy change. Mark the solvent t describe in thermochemical equations. ΔH in a group of reaction: Qualitative- Understand ΔrH can be influenced only by starting state and final state, no Hess Law describe matter how complex the reaction course. Quantitative Calculate ΔrH of new reactions by known reaction ΔH -explain Quantitative According to the known ΔH, design reaction course and calculate the ΔrH -design of new reactions. Figure 6. The relationship of the epistemic perspectives in ΔH of system 10 Based on these models, tests and interviews were designed to diagnose the misconceptions from high school students in learning thermochemistry. One of the most obvious problems is that some students in senior high school still make errors in the calculation of heats of reaction and ΔH. They cannot distinguish the system from the surroundings. It is hard for them to realize that Q and ΔH are aimed at opposite systems. Students should be able, when given a change to a defined system and its surroundings, to identify the direction of thermal energy transfer as either endothermic or exothermic. To help solve this problem in teaching, first, we advise teachers to build the concept of system and surroundings. Second, construct an energy diagram. It is an effective simple strategy that helps students imagine the energy change. Another problem we found in the interviews is in the ability to show significance of Hess’ law besides the calculation ΔH of a group of reactions. The epistemic performance level of most students is “explain”, but they find it difficult to reach the level “design”. In class, teachers may design activities and materials to guide students to determine the value of Hess law for determining energy options. One example is using the question “How can we use coal more scientifically?” as a leading question. In the class, teachers can let students investigate why coal gasification and liquefaction replace traditional direct combustion in industrial production. 11 Students can practice through the calculation of Hess law and experience the significance at the same time. The epistemic field that students know develops from matter to reactions and then to system. And the energy epistemic perspective deepens from temperature difference to reaction heat, then to enthalpy change. In high school, the two core knowledge themes in thermochemistry learning are heats of reaction and enthalpy change. In instructional design, these two should be of primary concern. Also, the significance of thermal energy transformation should not be ignored in teaching. Research on the epistemic model of electrochemical cell Chemical energy, heat, and electric energy can be interconverted into each other. In high school chemistry, the focus is on the two directions of the conversion. The first focus is chemical energy to heat and the second is chemical energy to electric energy. The primary cell is a typical model needed to understand the process, and it presents teaching challenges for secondary high school science teachers. Present research shows that researchers stress conceptual understanding and misconceptions. It seems that students have the ability to solve quantitative problems related to electrochemistry, but few can answer the qualitative questions involving conceptual understanding (Viola I.Briss & D. Rodney TNaX, 1999). Electrochemistry learning includes calculation and conceptual ideas. But students typically have difficulties with the conceptual ideas (Mansoor& Eleazar, 2003). Michael J. Sanger and Thomas J. Greenbowe (1999) selected 10 university textbooks to collect sentences and tables which may lead to misunderstanding of concepts, and presented some teaching suggestions. Some surveys indicate that the difficulties students have in understanding the primary electrochemical cell may come from these aspects: (1) identification of the anode and cathode; (2) the need for a standard half-cell; (3) direction of electrons path; (4) direction of electric current path in primary cells and electrolytic cells; and (5) prediction of cell potentials and reaction product (Garnett & Treagust, 1992; Michael & Thomas, 1997). The research helps us in knowing how students learn these ideas and the challenges they have, but it is necessary to analyze the related content in textbooks of high school and universities to build a key content system about primary electrochemical cells teaching and learning, and relate it to how students build understanding. Then the epistemic model can be constructed (Table. 4). In the table, the terms “describe”, “explain”, and “apply” are separately selected with the Macroscopic/microscopic, qualitative/quantitative, and unsystematic/systematic to express different levels in each perspective. Table. 4 Detailed epistemic model of electrochemical cell Field perspective Sub-perspectiv Category /level Results /performance e Potential difference Electrode reaction Matter Changes Macroscopic/micr oscopic Qualitative/ quantitative describe Describe the electrodes explain Analyze the direction of electrons transfer describe Realize the quantitative relationship in electrode reaction Know that electrodes have phenomenon 12 on explain apply Energy transformation Qualitative/ quantitative describe explain apply Electrolyte ionic diffusion Qualitative/ quantitative describe explain different activities that cause the transfer of electrons Understand electrons transfer from the perspective of potential difference. Write reaction equations of electrodes and the cell. Analyze the transfer of electrons from structure of reactants. Predict the production and electron number by charge conservation law. Choose electrode reactions and cell reactions according to conditions Choose electrode reaction pair according to potential difference. Know energy transformation in primary cell. Describe the energy relationship between reactants and products. Explain energy transform from the view of redox reactions separately in cell. Use the relationship between Gibbs free energy and potential difference to analyze the direction of cell reaction. Give some suggestions to raise energy transform rate. Predict the limit of energy transformation in a cell quantitatively. Understand the form of potential difference based on ionic diffusion. Know the relationship between ion concentration and potential difference Analyze how transmission rates of different ions influence the liquid (junction) potential. Use Nernst equation to discuss the relationship of cell potential and 13 ion concentration. apply ionic equilibrium Unsystematic-stati cs /systematicdynamic describe Describe the category of ions Describe the movement of ions based on electric neutrality. explain Analyze the movement of ions only in one kind of cells. Analyze the transfer of ions in a few kinds of cells. apply Closed circuit Electronic conductor wire Electrode material Qualitative Unsystematic/syst ematic Choose suitable electrolyte according to electrode reactions Choose suitable electrolyte according to cell reaction and conditions describe Know wire is the road of electrons explain Analyze the transfer direction of electrons apply Use wires to build a closed circuit describe Know electric charges move in/out of electrode materials explain Explain the function of electrode materials only when they involved in the electrode reaction Explain the function of electrode materials whether they involved in the electrode reaction or not apply Ionic conductor Unsystematic/syst ematic Choose supporters of electrolyte (electrolytic bridge or film) according to conditions. Choose the suitable concentration of electrolyte according to potential. Choose electrode materials to build the closed circuit based on electrode reactions. Choose electrode materials to build the closed circuit based on both electrode reactions and other conditions. describe Describe how the movement of ions helps to form the closed circuit. explain Explain the function of ions in electrolyte only when they 14 apply involved in the electrode reaction Explain the function of ions in electrolyte whether they involved in the electrode reaction or not Using electrolyte solution, build a closed circuit when designing a primary cell Using different supporters of electrolyte, build a closed circuit when designing a primary cell. According to the model, we designed assessment tools that measured senior students’ cognitive development regarding primary electrochemical cells. The instrument had good reliability and validity, which could be used for large-scale test. Our research shows there is a hierarchical development concerning high school students’ epistemic system at present. This demonstrates that our model is scientific. Meanwhile, chemistry learning and course sequencing affect the epistemic model and its development. Based on the above, our study proposes some suggestions for high school primary cell teaching. After comparing with textbooks, we came up with advice in terms of teaching. Figure 7 is a teaching model about cells resembling a coordinate system, which has two dimensions: principle and device. Inside the coordinate system, the analysis process such as identification of the anode and cathode, direction of electrons path, direction of electric current path, reactant and reaction product, can all be shown clearly. It is a functional model that is not only for teaching, but also for learning and even for assessment. Figure 7. A teaching model for electrochemical cells Research on curriculum content of quantum mechanics based on energy conception Why quantum mechanics? On the one hand, to answer this question “what is energy”, we have to deepen our research into particles that constitute matter. Energy comes from the force between particles in essence, including electrons and atomic nucleus. Quantum mechanics is the basis for understanding these particles. It is reasonable to research curriculum content of quantum mechanics in order to promote the understanding of energy. On the other hand, understanding chemical substances and reactions from an energy 15 perspective forms the foundation of chemistry thinking, which helps students to explain chemical phenomena and solve chemical problems. Also, students benefit from building correct conceptions and improving scientific literacy. Under the new high school chemistry curriculum in Mainland China, some energy concepts are introduced, such as energy level, ionizing energy, electronegativity and so on. However, teachers and students don’t understand the value of these concepts. Some surveys show that most high school teachers and students lack understanding of energy associated with these ideas. We believe that the energy conception is based on quantum mechanics and forms a unique way of thinking. It is necessary to build an epistemic model to answer the questions of how the curriculum content develops students’ energy conception. On the basis of analyzing textbooks related to quantum mechanics and structural chemistry, four energy understanding objects were established: atom, molecule, crystal, and chemical reaction mechanism. We built four epistemic models to explore students’ understanding, including epistemic perspectives, levels and performances. Seen from an energy perspective, one of the epistemic fields, the system of the atom, has three epistemic perspectives: particles in an atom and their relationships, atomic properties, and electron movement (Figure 8). These three are not independent, but are linked to each other. Figure 8. The epistemic perspectives of the atom system based on energy conception Knowing about the static structure of atom first will help build a better a dynamic structure understanding. Both the static and dynamic structure of the atom help explain atomic properties. And the dynamic structure, that is electrons movement, is essentially linked. Molecules can also be seen from energy perspective (Figure 9). One epistemic perspective has several sub-perspectives, and shows different epistemic levels. The model shows a thinking path. The perspective that electrons in individual atoms is the basis for us to understand the molecule system. Movement of electrons in a molecule is the key point to understand properties of 16 molecules. The property of molecules is a major theme in chemistry learning. It can be seen from a variety of energy values. Figure 9. The epistemic perspectives of molecule based on energy conception Similar to the epistemic perspective regarding molecules, the epistemic perspective regarding crystals include: particles in a repeating lattice structure and their relationship, electrons in subsystem before forming crystals, the movement of electrons in crystals, and properties of crystals. The first two perspectives are the starting point of research on crystals Research on chemical reaction mechanisms uses three main points: orbit theory, theories of energy and energy level diagram of molecular orbital (MO). First is the MO of reactants and products molecules, and the second is the movement of electrons among molecules. The third one is the problems about reaction processes, like mechanism, conditions, activation energy and transition state. These three points become the epistemic perspectives of chemical reaction mechanisms. (Figure 10) 17 Figure 10. The epistemic perspectives of molecule based on energy conception When building the perspectives of the above four epistemic fields – atomic, molecular, crystalline, and chemical reaction mechanisms – the implication of these ideas are: (1) in the quantization of energy, the smallest unit is hv; (2) the interaction of the old system results in a new system, electronic configuration renewal, and energy change (generally, energy of the new system is lower than the old one); (3) in determining effective interaction between orbits, whether MO or AO, three principles must be followed, that is matching of orbitals symmetry, similar energy and maximum overlap; and (4) electrons on orbits follow the law of lowest energy, Pauli exclusion principle, and Hunt Rules. The epistemic category/level includes from macroscopic/microscopic, qualitative/semiquantitative/quantitative understanding. Sometimes a new energy indicator means reaching a higher level. For instance, orbital wave function and orbital energy formula are quantitative marks. We believe that for high school students, thinking paths and the basic conception of quantum mechanics are the two core epistemic ways of energy understanding, much more important than specific knowledge. The first aim of quantum mechanics learning in high school is introducing new theories, which lead to application. The 21st Century is a time of quantum mechanics, and it is necessary for students to know about it, whether or not they major in college chemistry. The second goal of the study of quantum mechanics is building a basic thinking path of property research. When studying the property of atoms, students will realize that the properties are the performance of its own structure. Students can use electron movement as well as particles in an atom and their relationships to explain a specific property. This reminds students to recall previous chemistry learning. The third target is understanding basic quantum mechanics. For high school students, difficult knowledge like valence band is not as useful as the basic conception like orbital and quantization. This orbital is generalized to mean not a line but continuous motion of atoms, 18 molecules or electrons, and so on. About these particles, the continuous motion provides more information, such as about energy and angular momentum. The greatest differentiation between movement of these particles and the macroscopic world is quantization. In quantum mechanics, the orbital is a representation of the motion of particles, and the information about these particles such as energy and angular momentum is shown by four quantum numbers n/l/m/ms. It should be emphasized that specific knowledge serves basic conceptions. Discussion Worthwhile theories and results of research on teaching and learning have to be accepted by teachers and students and applied in class. The epistemic models we raised are the results of practice, and in turn serve practice more. We raise this to explain the process of cognition, reveal the learning map, and changes when students acknowledge specific concepts. By an epistemic model, we are able to explain the students’ development from two perspectives, gaining new epistemic perspectives and changing epistemic categories. A model is a detailed learning map of a specific concept. It is possible to predict the performance of students when they have learned new concepts. The model provides a basis for instructional design not only for researchers, but also for teachers. Under the big idea, energy, we focus on what is energy and energy transfer/transformation. Specifically, three themes in the high school curriculum emerge: thermochemistry, electrochemistry and quantum mechanics. These three themes serve as the research objects in which we want to answer these questions with respect to energy teaching and learning: 1) what should students learn; 2) what should students learn at different grade levels; and 3) how should these various ideas be taught. Every epistemic model shows various perspectives, categories/levels and results/performances, and reveals the essence hidden behind students’ performance in learning. It also helps teachers in designing key questions to use during class, choose strategies to use during class, and design assessments; in essence, it help teachers develop pedagogical content knowledge with respect to teaching energy at various grade levels. Our research on chemical energy transforming to thermal energy and electric energy has covered curriculum and teaching practices. In thermochemistry learning, the energy epistemic perspective deepens from temperature difference to heat of reactions, then to enthalpy change. In senior high school, the core in thermochemistry learning is enthalpy change. This should be the focus of instructional design. The microscopic cause of chemical energy is essential knowledge, that is “energy is always required to break chemical bonds, and energy is always produced when a bond is formed.” Also, the significance of thermal energy transformation should not be ignored in teaching. In electrochemistry, potential difference and a closed circuit are the two necessary components to an electrochemical cell. In learning and teaching, two dimensions, principle and device are two key points. The principle that chemical reactions in electrochemical cell, is caused by potential difference is a critical idea for students to understand. Devices ensure a closed circuit. The analyzing processes of identification of the anode and cathode, direction of electrons path, direction of electric current path, and the identification of the reactants and reactions product can be shown clearly in these two dimensions. But we still lack research on teaching practices related to the teaching and learning of quantum mechanics, which is one direction of study for us. For future study, we propose to use epistemic models to analyze energy misconceptions in specific topics, and provide advice on conceptual change learning and teaching strategies in detail. 19 References A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012). National Research Council. Committee on a Conceptual Framework for New K-12 Science Education Standards. Board on Science Education, Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press. The College Board. 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