| U.S. has carried out a reform of standards-based science curriculum, symbolized by "National Science Education Standards" issued in the1990s. However, the curriculum reform over10years seems ineffective, especially students showed poor performance in the international scientific test. In this regard, the United States carried out a profound reflection, generally considered the knowledge contained in the state science curriculum standards and the National Science Education Content Standards to be too broad, superficially covering a lot of scientific knowledge, thus the courses of "one kilometer wide and a foot deep " exist and students cannot improve and deepen the understanding of scientific core ideas with the grade increasing. Moreover, each of the U.S. science curriculum, classroom teaching and examination evaluation stands by its own side. To address these drawbacks, Washington, New Jersey initially amended their states’curriculum standards. The U.S. National Research Council also enacted the conceptual framework of the new National Science Education Standards in2012. These newly revised science curriculum standards organize knowledge around a small number of core ideas and provided each of the core idea with the learning progression during12years, which means the degree of understanding about the core idea that students of all grades should reach, so that students continued to deepen the understanding of the core ideas during the period of the elementary, middle and high school. Organizing and allocating subject knowledge around core ideas and developing understanding about core ideas though learning progressions can promote the formation of good structure of knowledge, thorough understanding of core ideas, and the ability to solving problems. It has become the core idea of modern science curriculum reform.At present, China has conducted physical curriculum reform based on the curriculum standards for about10years. The inefficiently alignment on a comprehensive science curriculum and subject curriculum from elementary to high school stage has affected the development of ability of students to solve problems and thinking logically. Therefore, the investigation of what the high-school physics core ideas are and the construction of the core ideas’learning progression are significant to the promotion of the alignment of curriculum, learning, teaching, and examination.As above, the problems to be solved in this study are:(1) What the high-school physics core ideas and their connotations are?(2) What the "learning progression" of each core ideas are? That is, what level of understanding should the students of elementary, junior high, high school reach to the high-school physics core ideas?In order to achieve the above purpose, the study consists of two main research contents. Firstly, the investigation research of the core ideas of our high-school physics. By text analysis on the physics textbooks of high school, the mechanical, electrical, thermal, optical, and modern physics ideas are combed and the core ideas of high school physics are summarized. To verify the reasonableness of the study, a survey of the core knowledge by high-school physics teachers was done. According to the statistical frequency of these knowledge appearing in the questionnaire, the author test and adjust the core ideas generalized. Secondly, the study of the learning progression of the high-school physics core ideas. The author studys the knowledge directly related to core ideas in the domestic and foreign physics/scientific curriculum standards of basic education, makes a special effort to analyze the knowledge around certain core idea in these standards which should be studied by students of certain phase of studying, calculates the frequency of these knowledge and analyze the connotation of them. Moreover, the author combs through the research from domestic and abroad on the understanding of core ideas by students, makes a special effort to analyze the typical misconceptions of certain core idea by students of every phase of studying and the teaching efficiency of certain core idea in every phase of studying. Synthesize the comparison of domestic and foreign standards and the combing of related research evidence, the author builds the learning progression of these three typical core ideas as "conservation of energy","stable electric field," Force and Motion ".As above, the conclusions are obtained as follows:(1)There are11core ideas of the physics in high school, namely force and motion, energy and momentum conservation, stable electromagnetic fields, dynamic electromagnetic field, molecular kinetic theory, the laws of thermodynamics, preliminary geometrical optics, preliminary physical optics, atomic structure, changes of the atomic, wave-particle duality and the theory of relativity. The author details the meaning of each of the core ideas. Through the survey on high-school physics teachers, the11core ideas in the five areas of mechanics, electricity, heat, light and modern physics could covers very well the core knowledge of the teachers in corresponding areas.9of the11core ideas get higher frequency, which means that the core ideas selected and their connotations is basically reasonable. Two core ideas of "Laws of thermodynamics" and "wave-particle duality and the theory of relativity" get relatively minimum frequency. By analysis, the "wave-particle duality and the theory of relativity "should be remained as an core idea, but whether the laws of thermodynamics should merge with other core ideas needs further study.(2)The author builds "learning progression" for the core idea of "energy conservation".As to the definition of energy and manifestations, pupils should learn the common forms of energy (light, electricity, heat, sound), but also recognize that the movement is a form of energy, not to learn the concept of energy. Junior high school students began to learn the kinetic energy, potential energy, the nature of the hot (not to learn the internal energy) as well as nuclear energy(preliminary), to learn the approximately initial energy concept. High school students quantitatively understand the kinetic energy, potential energy, begin to learn internal energy, electric potential energy, nuclear energy(further), and learn more precise and abstract concept of energy (from the conservation point of view);As to "the transfer, transformation and conservation of energy", pupils only learn the typical phenomenon of energy transfer and conversion, involving light, electricity, heat transfer, and electrical energy, thermal energy conversion. Students in Junior high school continue studying further about the heat transfer (transfer mode, explanation of heat conduction by using the molecular kinetic theory), electrical energy conversion and transfer, and start learning the mutual conversion between the kinetic energy and potential energy, the transfer of kinetic energy though collision(preliminary), the concept "energy can transform and transfer "as well as the concept of energy conservation in a half quantitative terms. High school students learn more abstract and complex phenomenon about energy transfer and transformation, involving radiation and its essence, energy transfer and conversion though collisions, the mechanism of the release of atomic energy and nuclear energy, the conversion of electric potential energy, and quantitatively master the conservation of mechanical energy and the law of energy conservation.As to the relationship between work and transfer/transformation of energy, students from junior high school start learning some typical examples of energy conversion during the process of doing work. High school students learn the relationship between work and change of energy quantitatively and quantitatively, especially the quantitative relationship between work and change of kinetic/gravitational potential energy.(3) The author constructs the "learning progression" for the core idea of "stable electric field".As to the electrostatic field, primary school students know that the objects can attract other objects at a distance after electrification by friction. When they are in the sixth grade, they can distinguish between static electricity and current. Junior high school students know the classification of the charges as well as the interaction between the positive and negative charges. High school students learn the microscopic nature of electrification, the Coulomb’s law, the electrostatic field, the electric field strength, the electric potential difference, the electrical potential energy, and the electric field lines, without learning the concept of the electric potential.As to the steady current, pupils should recognize that a complete and closed loop is the premise of the current formed, electrical components working properly, and be able to recognize each of the elements of the circuit and their functions, especially the switch. Junior high school students start learning the concept of the voltage, current and resistance, the causal relationship between voltage and current, and the distinction between the concept of current and electrical energy. Junior high school students should understand the usage of the circuit diagram, short circuit, the uses of voltmeter and ammeter, qualitatively master Ohm’s law, recognize that a resistor added to an arbitrary position of the simple series circuit will cause the same effect on the entire circuit, recognize the changes of electrical elements in the external circuit will influence the current in main circuit. Junior high school students should understanding of the series circuit, parallel circuit and the characteristics of the voltage and current in them, particularly the allocation of the voltage in series circuit and the allocation of the current in parallel circuit. In addition, they should qualitatively grasp the electric power and Joule’s law. High school students should understand the microscopic mechanism of the current from the perspective of the electric field, quantitatively grasp Ohm’s law, and know the affect of the local circuit changes on the entire circuit. High school students should quantitatively grasp the characteristics of resistors in series and parallel circuits, qualitatively master the Resistance law, and quantitatively grasp the electric power and the Joule’s law.(4) Regarding to "kinematics" and "dynamics" included in the core idea of "Force and Motion", the author construct the learning progression for each of them.On Kinematics aspects, primary school students learn the various forms of an object motion, recognize the need of another object when describing the location of one object and the need of tracking the changes in its position when describing the movement of the object. Junior high school students grasp the concept of speed quantitatively and the relationship among speed, distance and time, and recognize the need of position, direction of movement and speed when describing the motion of one object. Junior High School students should learn the uniform linear motion, and use distance-time image to describe motion. High school students start grasping the concept of acceleration and learning related principals about uniformly accelerated linear motion. High school students distinguish between scalar and vector, e.g. displacement and distance, speed and rate; distinguish between instantaneous and average values, e.g. instantaneous speed and average speed. Motion is described by displacement-time image or speed-time image.On dynamics aspects, primary school students learn to forces which could change the shape of and the motion of an object, initially understand the existence of friction which hinders the movement. Junior high school students should be aware of the effect of imbalance forces on the object motion, recognize objects at rest in life often be affected by a pair of balanced forces, and recognize that the interaction of the forces is always mutual. Junior high school students should recognize that the object would remain stable or uniform linear motion with a pair of balance force or without force when they are in the9th grade. The high school students continue to study Newton’s first law further, and know that objects maintain the speed of the moment when losing force(to inertia). The high school students learn Newton’s second and third law, understand the simultaneity of force and acceleration and the real reason of the emergence of acceleration. The high school students learn the projectile motion, circular motion, and the causes of both, and learn the planetary motion in which gravitation is the centripetal force.In light of the conclusions as above, this study provides recommendations to teaching, compiling of textbooks and subsequent research. |
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