Rasch Model-based Evaluation Research Of "Chemical Equilibrium Concept" For Senior High School Students

The 2017 edition of chemistry curriculum standard expounds the requirements of basic concepts of chemistry:It is required that the curriculum can guide students to form the core concept of chemistry,the compulsory curriculum can reflect the basic concept of chemistry,and teachers' teaching should play the role of the basic concept of chemistry.Therefore,it is of great significance to cultivate students' basic concepts of chemistry.The research on the evaluation of the basic concept of chemistry shows an increasing trend year by year,but it is found that there is less research on the concept of chemical equilibrium by consulting the literature.This study refers to Professor Wang Lei's classification of the ability level of chemistry discipline,and combines the requirements of the new curriculum standards and high school chemistry textbooks for the concept of chemical balance,so as to operationalize the concept of chemical balance into an evaluation index system.The system consists of three primary indicators and nine secondary indicators,and each secondary indicator corresponds to 1 ? 2 basic understandings,According to the index system,an evaluation tool composed of 15 questions is compiled.The analysis software of Rasch model is used to test the evaluation tool for two rounds.Finally,the measurement tool whose reliability and validity meet the requirements of Rasch model is obtained.Taking a high school student in Harbin,Heilongjiang Province as the sample,200 students were selected from two classes of senior two and senior three,both of which were composed of ordinary classes and key classes.A large sample test was conducted on the level of students' concept of chemical balance.Analyze the level of students' concept of chemical balance from different dimensions.The specific description is as follows.(1)On the whole,the average ability of the subjects is-0.44,which is at the level of "learning and understanding".In terms of the proportion of the number of people,the level of chemical balance concept of the subjects is mostly concentrated in the level of "learning and understanding" and "application and practice",and few students can reach the level of "migration and innovation".(2)By analyzing the level of students in each dimension,we know that in the dimension of learning and understanding,the average ability of students is-1.83,reaching level 2(general correlation).In the dimension of applied practice,the average ability of students is-0.43,reaching level 1(analysis and interpretation).In the dimension of transfer innovation,the average ability of students is 1.82,and students reach level 1(complex reasoning).(3)The analysis of the level of chemical balance view of students in different grades shows that the average ability of students in grade two is-0.56,which is at the level of learning and understanding,and the average ability of students in grade three is1.25,which is at the level of application and practice.According to the results,the level of students' chemical balance tends to increase with the rise of grade,and the test of SPSS software shows that there are significant differences in the level of students' chemical balance view in grade.(4)By analyzing the level of students' view of chemical balance in different classes,we know that the level of students' view of chemical balance in key classes(1.37)is better than that in ordinary classes(-0.56),and SPSS test shows that there are significant differences in the level of students' view of chemical balance in classes.(5)The analysis of the level of chemical balance view of students of different genders shows that the level of girls(0.89)is slightly higher than that of boys(0.86),and the stability of girls is higher than that of boys.The SPSS test shows that there is no significant difference in the level of students' concept of chemical balance between genders.Based on the analysis of the comprehensive evaluation results,this paper puts forward the teaching strategies to promote the development of senior high school students' concept of chemical balance.Finally,it expounds the conclusions and shortcomings of this study.