A Diagnostic Research To Detect Students' Conceptual Understanding Of Isomer

Concept is the basic content that embodies the discipline thought.It is of great meaning for subjects teaching to timely and effectively probe students' conceptual understanding.The two-tier multiple-choice method(answer section + reason section)is the main method of the diagnostic means of conceptual understanding,but it has many defects,one of which is ignoring students' psychological factors.Recent years has witnessed the increasing popularity of a new way in foreign countries named the four-tier diagnostic method(answer section + confidence rating of answer section + reason section + confidence rating of reason section),which can avoid some problems of the two-tier one.However,the research and the application of this method is still in its infancy in China,and there is no complete case in the organic field at present.Therefore,this study compiles “the four-tier multiple-choice diagnostic test about isomer concept”(ten items)to probe 385 high school students' basic understanding of isomer conceptual system,and research the number,degree and typicality of misconception.What's more,using “the writing test about isomers” to give an in-depth analysis of students' concept application.Finally,based on the data results and interviews with students,discuss the causes of the problems and put forward relevant suggestions.Five research results are as follows:(1)Through combing relevant literature about conceptual understanding,distinguish the difference and connection between some terms such as “misconceptions”,“alternative concept” and so on,sort out the development context of terms and affirm the importance of correct use them.(2)The four-tier diagnostic test can explore students' concept understanding from many angles and aspects,including Scientific Concepts,Lack of Knowledge,Misconceptions and Errors,which is more objective and fair than the second-tier and third-tier diagnostic test.(3)High school students have different degrees of mastery in different content dimensions of the concept system of isomers(G1 understand the concept of isomers,G2 distinguish isomer concept from other confusing concepts,G3 master the category of isomers,G4 determine the number of isomers),and the understanding is different between schools(municipal key and non-municipal key)and gender(male and female).(4)22 misconceptions are identified: 10 are moderate misconceptions,12 are severe misconceptions,and 5 are typical misconceptions.There are various reasons for students' misconceptions,including teachers' teaching methods and educational idea,students' individual differences and psychological characteristics.(5)Students have great difficulty in using concepts,especially the use of thinking strategies and the principle of equivalence.The students who get full marks have a definite thinking tendency in writing isomers.