The Research On The Learning Of Chemical Reactions About "macro-micro-symbol" Threefold Representation

Chemistry is a subject that research constitutes, structure, property and changing regulationof material on the molecular and atom levels.The property embodies macroscopic changes. Themicroscopic constitutes and structure is the basis that comprehends the properties and changes.And the chemical symbol describes the macroscopic matter and changes regulation from themicroscopic level, becoming the bridge to connect the macro and micro world. Therefore,learners will develop three special representations to the material: macroscopic representation,microscopic representation and symbolic representation. It can be the essence of chemicallearning for learnners.Chemical reaction is the core of chemistry,and it is also a central focus in the chemicalresearch.For students, the learning of chemical reactions runs through the study of chemicalknowledge. Macroscopic representation, microscopic representation and symbolic representationare respectively used in different parts of the chemical reactions learning. Students ’understanding of the chemical reaction is from macroscopic(such as new substancesgenerate,accompanied by light or heat phenomenon) to microscopic(such as reactant moleculesbreak down, and atoms,composed of molecules,regroup into new substances), as well assymbolic(such as chemical symbol, chemical, ion type and chemical equation). At the macrolevel, the basic feature of chemical reactions is the formation of new substances. At the microlevel, to understand chemical reactions, from the view of molecular, atomic , the essence of thechemical reaction is that the reactant molecules break down, and atoms, composed of molecules,regroup into new substances.This research focuses on five issues:the status quo of domestic and international research onchemical reactions and macro, micro and symbolic representations, the connotation of threefoldrepresentation, the scope of the study of chemical reactions, and the research on the learning ofchemical reactions about“macro-micro-symbol”threefold representation.We investigate the levels of threefold representation of different students on understandingchemical reactions by using questionnaire, control law and so on. We choose students from three grade levels of a senior school.And we mainly find six problems in this investigation: (1)Students’ macroscopic representation is better, but microscopic representation and symbolicrepresentation are weak;(2) Students’macroscopic, microscopic and symbolic representationsinformation is more concentrated, and the number of static composition is more than dynamiccomposition;(3)From different representation information, student’s understandings aboutchemical reactions at macro, micro and symbolic representation levels are different;(4)Student’sunderstandings about chemical reactions at macro, micro and symbolic representation levels donot improve with the increase of grade;(5)Students’ ability of relating two kinds ofrepresentations is better than relating three kinds of representations;(6)From differentrepresentation information, student’s understandings about different parts of chemical reactionsare different.At last, we preview prospect for future research along with analyzing the problems existingin the thesis.This paper provided a new view for educational research of chemistry teaching. It possessesvery positive academic and practical significance for enriching learning theory of chemistry,accelerating the development of teaching practice and promoting students’comprehension tochemistry.