Research On Instructional Strategy Of "Machinery And Work" Preconception Transformation In Junior Middle School

Physical concept is the most important foundation of physics and the basic element of physical knowledge system.Previous research have shown that wrong preconceptions will affect the establishment of scientific concepts,and the effective transformation of preconceptions will help students to construct scientific physical concepts.This research is based on constructivism learning theory,Ausubel's meaningful learning theory and Vygotsky's "zone of proximal development" theory,using literature method and questionnaire research methods.According to the requirements of "machinery and work" in the Physics Curriculum Standards for Compulsory Education(2011 Edition),the questionnaire was developed in combination with the problems found in the second volume of textbooks and teaching practice of Grade 8 Physics in Beijing Normal University edition.Questionnaire survey is used to analyze students' preconceptions in "machinery and work" and its causes.The investigation shows that students have some wrong conceptions about "lever","pulley","work" and "mechanical efficiency" before learning "machinery and work",the main causes of false preconceptions are: the influence of existing knowledge;the influence of life experience;the influence of everyday language;Confusion of memories.On the basis of investigation and analysis,combining with existing research results,the teaching strategies for the pre-concept transformation of "machinery and work" are determined as follows: Teaching strategies based on cognitive conflict and teaching strategies based on analogy and metaphor.Through the analysis of questionnaire survey,it is shown that the teaching strategies adopted in this study can effectively change students' preconceptions.Based on the application of preconception transformation teaching strategies and the investigation of pre-concept before and after teaching,this paper puts forward teaching suggestions for the pre-concept transformation of "machinery and work" : Before physics concept teaching,a comprehensive understanding of students' previous concepts can help students better establish physics concepts;The teaching strategies to promote the pre-concept transformation should be selected and applied according to the actual teaching situation;Using the teaching strategy based on cognitive conflict,we should not only pay attention to arouse students' cognitive conflict,but also pay attention to the process of solving the cognitive conflict;After the new concept is established,it needs to be applied in the context to promote the real transformation of the previous concept.