A Study On The Composition And Evaluation Of Chemistry Teachers’ Teaching Representation Ability

Teaching representation ability is an important part of teachers’ ability and an important aspect of teachers’ professional development.Effective teaching representation is very important to chemistry teaching.The improvement of teachers’ teaching representation ability has positive significance to promote effective teaching.This study systematically researched the composition and evaluation of the representation ability of chemistry teaching,clarified the connotation of the representation ability of chemistry teachers,constructed the theoretical framework of the development level of the representation ability of chemistry teachers,developed the measurement tools of the representation ability of chemistry teachers,and analyzed the level performance and differences of the representation ability of chemistry teachers.Firstly,this research combs and analyzes the literature related to teaching ability and teaching representation,and expounds the current research progress of teaching representation in the field of chemistry from the aspects of concept definition,type,influencing factors,assessment methods,etc.On the basis of clarifying the concepts of representation and teaching representation,this paper specifically analyzes the connotation composition of teaching representation ability in chemistry teaching from three aspects.Then,combining the PCK theory,SOLO classification theory and chemistry teaching ability constitution,the theoretical framework of the evaluation of chemistry teachers’ teaching representation ability is constructed,and the representation ability of chemistry teaching is divided into four levels: limited level,basic level,development level,and excellence level.Limited level means that teachers have a preliminary understanding of teaching representation and can distinguish macroscopic representation,microscopic representation and symbolic representation.However,when the teaching content is presented in the form of specific teaching representation,the characteristics of the representation field and students’ concept understanding cannot be related.The basic level is that teachers can associate the representation form with the representation information,apply a variety of representation forms in teaching,and choose the representation form based on the characteristics of the field of representation in teaching.However,the representation application in the macro field,micro field and symbol field is a process display,and has not realized the organic correlation.Teachers at the development level can establish the substantive correlation between the teaching representation and the conceptual understanding of students.It can guide students to carry out effective cognitive activities in the process of presenting teaching representations,and design the internal correlation between teaching representations based on the needs of students’ conceptual understanding.Excellent level of teachers can comprehensively consider the characteristics of college entrance and the need of concept construction,and can comprehensively analyze and optimize teaching representation to point to students’ deep concept understanding.Secondly,this study combined teacher interviews and open questionnaires to collect the application of teachers’ teaching representation,and developed test items based on the analysis of the qualitative data results and the framework level of teaching representation ability.Through the revision and improvement of two rounds of test,the Rasch model analysis scale has good reliability and validity,which indicates that the test data and the constructed model of chemical representation ability level have good consistency.The framework of chemistry teachers’ teaching representation ability level can effectively describe the development of chemistry teachers’ teaching representation ability.Using this scale to test large samples of pre-service teachers and in-service teachers,it is found that in-service teachers have higher representation ability in chemistry teaching than pre-service teachers.Further,taking teaching age,teaching period,type of current teaching school and professional title as the research classification variables,this paper carries on statistics and analysis to the performance of the sample teaching representation ability of teachers.The results showed that the teachers’ representational ability of chemistry teaching increased with the increase of teaching years,and the novice teachers(1-5years of teaching years)were at the basic level.The average ability of skilled chemistry teachers with 6-15 years of teaching experience is 1.01,reaching level 3--development level.The mean value of teaching representation ability of chemistry teachers with more than 16 years of teaching experience is the highest,which is 1.91,reaching level 4--excellent level,which is in line with the level performance of expert teachers.By comparing the representation ability of teachers in different teaching sections,it can be seen that the representation ability of high school teachers(mean 1.47)is significantly higher than that of middle school chemistry teachers(mean 1.05).By comparing the teaching representation ability of teachers in different types of schools,it is found that teachers in municipal schools have a higher level of teaching representation ability,with an average value of1.51,while teachers in rural schools have a lower level of teaching representation ability,with an average value of 1.17.Teachers’ teaching representation ability shows a trend of gradual decline,but there is no significant difference.By comparing the teaching representation ability of teachers with different professional titles,it is found that the level of professional titles is positively correlated with the level of teaching representation ability.The higher the professional titles are,the higher the level of positive correlation is.The mean value of teaching representation ability of teachers with senior titles was the highest(2.54),followed by that of chemistry teachers with senior titles in middle school(2.07)and that of first-level middle school teachers(1.68).The teaching representation ability of the teachers with the above three titles all reached an excellent level.The mean value of teaching representation ability of teachers with secondary school titles is 0.62,which can just reach the development level.The average level of representational ability of teachers during the internship is 0.37,which is the basic level.Finally,one expert teacher and one novice teacher are selected to analyze and compare their application of teaching representation under the teaching theme of "law of Conservation of quality" respectively,and analyze teachers’ real teaching representation ability from a qualitative perspective.The research results show that expert teachers’ teaching representation ability has the following characteristics:(1)Be able to choose the form of teaching representation as a whole and consciously establish the organic correlation of teaching representation.(2)Be able to design high-level students’ cognitive activities and establish substantial correlation between teaching representation and students’ effective cognitive activities to implement the representation function.The innovation of this study lies in the construction of a framework of chemistry teachers’ teaching representation ability,which can be used to effectively measure the level of teachers’ teaching representation ability.Moreover,the development characteristics of teaching representation of novice and expert teachers can be found by in-depth description of individual cases,so as to provide targeted references and suggestions for the development of teachers’ teaching representation ability.