Learning Progression Study Of High School Electrolyte Solution Concept

The theme of electrolyte solution captures many core concepts of chemistry disciplines and occupies an important position in the knowledge system of chemistry disciplines.Learning progression is a description of the typical development path of students’ cognitive and thinking skills,and is of great significance in improving curriculum,teaching and evaluation.Therefore,this study attempts to construct a learning progression of the concept of electrolyte solution,and design teaching based on this,so as to realize the advanced development of students’ understanding of the concept of electrolyte solution.The research comprehensively used literature analysis method,questionnaire survey method,interview method and other methods to conduct research.The construction of a theoretical framework for learning progression of electrolyte solution concept is the basis of this research.Through the review of learning progression and electrolyte solution research,the typical research paradigm of learning progression and the unsolved problems of advanced study of electrolyte solution were clarified,so as to limit the research scope of this study to soluble stable electrolyte solution system,and the literature research method,questionnaire survey method,interview method and other methods were used to conduct research.On this basis,combined with the analysis of course standards and teaching materials,the two advanced dimensions of "ionization" and "hydrolysis" were extracted.Drawing on the "discipline understanding method" of Wang Lei and others,the "knowing object","cognitive angle" and "cognitive thinking" were determined as advanced variables,in which the "cognitive object" and "cognitive angle" variable levels were divided by analyzing the course standards and textbook content of the compulsory and elective sections,and the "cognitive thinking" variable was presented using the "chemist framework",so as to obtain the theoretical framework of learning progression of the concept of electrolyte solution.In order to test the effectiveness of the theoretical framework,this study developed an advanced measurement tool for learning progression of electrolyte solution concept,and finally obtained a measurement tool that meets the requirements of the Rasch model through two rounds of testing,and revised the advanced theoretical framework of learning based on the results of large samples,and obtained the learning progression of electrolyte solution concept: in the ionization dimension,students at level 1 determine whether the substance is an electrolyte,and can use ionic equations to represent the ionization process of strong acids,strong bases and common salts.Know the relationship between ionization and macroscopic properties such as acidity,alkalinity and conductivity of the solution;Level 2 students can identify weak electrolytes,standardize the ionization process of solvent water and other simple weak electrolytes,know the influencing factors of ionization equilibrium and ion product of water,know the representation and meaning of ionization equilibrium constants;Level 3 students can understand solutions from a systematic perspective,analyzing the interactions between particles in simple solutions,the types and quantities of particles,and the macroscopic properties of solutions from both qualitative and quantitative levels.Level 4students use canonical ionization models for reasoning and purposefully analyze the ionization of substances in complex solutions.In the hydrolysis dimension,Level 1 students know the definition of salt hydrolysis and remember common hydrolyzed salts and their acidity and alkalinity;Level 2 students can write simple hydrolysis equations through mechanical combination of ionization equations,and can describe and explain the hydrolysis process and acidity and alkalinity of common hydrolyzed salts;Level 3 students can understand the essence of salt hydrolysis,analyze the influencing factors of salt hydrolysis,and recognize the types and quantity changes of particles in simple solutions.Level 4 students reasoned based on the idea model of aqueous solutions,analyzing the particle action in complex solution systems and the results.Model is the existence of explicit thinking,and reasoning based on the model and using reasoning to improve the model are of great significance to students’ thinking development.In this study,the construction of aqueous solution analysis thinking model is the core,and the teaching is designed with evidence reasoning as an auxiliary means.In order to verify the effectiveness of teaching intervention,experimental and control groups were selected to carry out teaching practice.According to the test results,the overall level of conceptual understanding of the experimental group was higher than that of the control group.Follow-up analysis and interviews were conducted on the learning process of some students in the experimental group,and it was found that the aqueous solution analysis thinking model and reasoning methods could effectively improve students’ thinking ability when solving simple problems.The cognitive perspective and thinking path of high-level students in solving problems are more consistent with the teaching model,which indicates that teaching intervention has an obvious role in promoting the advanced development of the concept of electrolyte solution.The innovation of this study includes two aspects: first,it specifically describes the students’ learning progress on the concept of electrolyte solution;Second,the teaching strategy to promote the effective and advanced development of students’ electrolyte solution concept was proposed and practiced.