Practical Research On Constructing Junior Middle Students Micro-Particle View Based On Macro-Picro-Symbolic Triple Representation

Chemistry is a natural science that studies the composition,structure,properties and variation of matter at the molecular and atomic levels.Macro-change reflects the nature of matter,and micro-theory is the basis to understand nature and grasp the nature of change,but chemical symbol scientificly and concisely expresses the nature of macro-matter and its law of change,which becomes the medium between macro-and micro-level.The characteristics of chemistry subject determine that the learners form the unique macro,micro and symbolic representations of matter in their psychology.Therefore,the study of chemistry from the perspective of triple representation becomes an effective approach to chemistry teaching and learning.The concept of chemical particle is one of the core concepts of chemistry learning in middle school.The new curriculum reform of chemistry requires that the teaching mode should be aimed at cultivating students scientific accomplishment and carrying out chemistry teaching based on cultivating the basic concept of chemistry.The purpose of this study is to guide the students to construct the micro-particle view from the aspects of perception,understanding and application through the teaching design and teaching strategy based on the macro-micro-symbol triple representation of junior middle school chemical particle view.So as to enhance students interest in chemistry learning and promote their scientific literacy.Based on the existing research literature on particle view,guided by constructivism learning theory and cognitive discovery learning theory,this thesis chooses science and education edition of junior high school chemistry textbook as the research model,and aims at cultivating junior middle schoolstudents micro-particle view.First of all,this paper analyzes the characteristics of the knowledge presentation of particle view in textbooks and the basic requirements of curriculum standards for the construction of students micro-particle view,and finds out through the investigation that students can not understand the concept of micro-particle.The micro-knowledge can not be used to explain the macro-material changes and the matter can not be distinguished from the micro-point of view.Therefore,on the basis of defining the cognitive level of the students micro-particle view,this paper puts forward the concrete teaching strategy of using triple representation to cultivate the students micro-particle view.These strategies include taking experimental exploration to lead students into the micro-world,using the model to build macro-and micro-bridges,leading students to explain the macro-facts and phenomena with the micro-particle view,and so on.Secondly,by analyzing the forming process of students concept of particle and combining their educational and teaching experience,we choose "particle-molecule","particle-atom" and "expression of material composition".The four contents of "reaction of Acid and Base" are designed for teaching.Finally,the teaching practice of the designed case is carried out,and the teaching based on triple representation is discussed to master the concrete chemistry knowledge,construct the students micro-particle view,and cultivate the students thinking ability and problem-solving ability.In the experimental class,the students in the experimental class can explain some chemical problems from the micro-point of view through the traditional teaching in the ordinary class.After a semester of teaching practice,the students in the experimental class can explain some chemical problems from a micro-point of view.The students triple representation consciousness and ability have been greatly improved,and their academic achievements have been improved significantly.The results show that the teaching design and teaching strategy based on triple representation can guide students to master effective learning methods,and the effect of training junior high school students chemical particle view is obvious.It is beneficial to the independentconstruction of the knowledge network of the students micro-view,enhances the students understanding and application of the micro-knowledge,and plays an important role in the cultivation of the students core accomplishment.