Practical Research On Variable Control Method In High School Chemistry Experiment

With the promulgate of the opinions on the implementation of college entrance examination reform(2014),the proposal of The Core literacy of Chinese students(2016),and the release of the revised new curriculum standards(2020),China's policy orientation in basic education shows that the teaching based on the core literacy of the subject is imperative.The scientific method is an important part of the core literacy of chemistry,so in chemistry class,the scientific method is an essential learning content.This study is based on the teaching content of the 2019 Edition of The Chemistry textbook for Senior High School published by People's Education Press(hereinafter referred to as the new Textbook for People's Education Edition),aiming to improve students' attention to scientific methods through teaching practice.Taking the new textbook of senior high school chemistry as an example,this paper discusses the necessity of presenting scientific method in the new textbook,interprets the connotation and classification of scientific method,analyzes the compiling characteristics of scientific method in the new textbook,and selects the application of variable control method in the new textbook for further research,and puts forward the corresponding teaching enlightenment.This paper is elaborated from five parts:The first part,preface.From the social background,subject background,revised new curriculum standard,new textbook of people's Education edition and college entrance examination topics in recent years,it is found that high school chemistry education attaches more and more importance to scientific methods.The scientific method is an important part of the core literacy of chemistry.The new textbooks focus on highlighting the scientific method,involving different types of scientific method.With the design of "method guide" and other related columns,the scientific method system of new textbook is constructed.The second part,related concepts and theoretical basis.Define chemical experiment,variable control method and other related concepts,and the relevant theoretical basis,such as philosophical theoretical basis,adolescent cognitive characteristics are described.Under the guidance of relevant theories,it is helpful to understand the cognitive characteristics of students to carry out the teaching of variable control method in chemical experiments.The third part,Practical research of variable control method in high school chemistry experiment.This paper analyzes and summarizes the experiments of applying variable control method in the new textbook of People's education edition,arranges the links between the experiments and knowledge points of applying variable control method in compulsory and selective compulsory chemistry of high school,and puts forward the general idea of using variable control method to solve problems.In order to study the application of variable control method in high school chemistry experiments,the author chooses two classes with similar chemistry foundation and similar ability levels as the research objects.One class is the experimental class,which emphasizes variable control method in chemistry experiment teaching,and the other class is the control class,which carries out routine teaching.In the practice research,the author chooses the rate and limit of chemical reaction as the subject to carry out teaching.Experimental class establishes teaching model under the guidance of the new curriculum standards,designs experimental scheme with the multi-level,multi-angle application of variable control method.then,Conducts experiment after teacher-student communication and evaluation.Introduce variable control method in the first teaching practice,teachers improve the experiment scheme of the effect of temperature on the rate of chemical reactions,under the teacher's guidance,students design experiment scheme according to different environment ","other same conditions",and draw up the experiment scheme of the effect of concentration and the solid surface area on the rate of chemical reaction.With the help of digital experiments,students collect evidence to confirm hypotheses,draw conclusions,and finally summarize the definition of variable control method.In the teaching of "Rate and Limit of Chemical Reaction",students are fully mobilized to conduct scientific inquiry by using variable control method,but their ability to find variables,shield irrelevant variables and quantitatively design experimental schemes is still weak.Therefore,the teaching case of "Exploring the influence of concentration on chemical reaction Rate" is selected for teaching practice again.Under the guidance of variable control method,with the reaction of oxalic acid and acid potassium permanganate as the principle,students design the experimental scheme.Based on the design and evaluation of three different levels of concentration schemes,the concrete connotation of variable control method is generated.In the two teaching practices,students participate in the classroom actively.Under the guidance of teachers,students complete all experimental activities while arguing and complementing with each other and constantly deepen the understanding of variable control method.The fourth part,posttest implementation and result analysis.After the teaching,questionnaire survey and interview were conducted for the experimental class,and tests were conducted for the experimental class and control class to collect and analyze evidence and obtain experimental results.The fifth part summarizes the research results of this paper and looks into the future.Through theoretical and practical research,the final conclusion is that the teaching mode focusing on scientific methods,such as variable control method,is effective,which can improve students' participation to a certain extent,and achieve the expected effect of cultivating students' ability to analyze and solve chemical problems.In teaching,the method line runs through the whole teaching practice,and the explicit thinking process and variable control method promote the transformation from knowledge to ability accomplishment.