Middle School Chemistry "redox Reaction" Learns Advanced Research

This study is a fundamental study of chemistry curriculum and pedagogy in middle school. The main purpose is to construct learning progression of theme of"redox reaction" in chemistry in the middle school, describing how perfect gradually the students’ understanding of the theme is developing.This study has gone through the following stages. First, this study analysed systematically relevant literature in recent years learning, and make learning progressions theory and cognitive development theory as the theoretical basis of this study. Then, through studying ontology of the subject, curriculum documents research and study the students’ understanding of the theme, this study initially constructed factor model for this learning progression. The factor model consists of four dimensions which are congnitive issues, cognitive object, cognitive pattern and cognitive task. This model will recognize cognitive objects and cognitive pattern as variables of this learning progression, and define how the development of students’cognition is reflected in the performance of these three core issues which are redox reaction essence, the occurrence of redox reaction and the energy in redox reaction.All of above form a hypothesis of learning progression which describes the students’understanding of redox reaction. Then, through developing the test tools by using Rasch model based on Item Response Theory and implementing empirical test with sample of students (including pre test and formal test), this study checked and revised hypothesis of learning progression to form fine framework of learning progression which describes how subtly the students’s understanding is developing.The study found that the students on the "redox reaction" learning progression can be divided into five levels, each level and corresponding content as follows:Level 1: the understanding of matter based on macroscopic view - gain or loss of oxygen;Level 2: the understanding of matter based on macroscopic view - valence change;Level 3: the understanding of single reaction based on macroscopic view -electron transfering;Level 4: the understanding of complex chemical reactions based on macroscopic view - electron transfering;Level 5: a precise understanding of the complex environment based on macroscopic view - electron transfering.At the same time, through the analysis of the test results, this study concluded the relationship between the levels and the grades, mainly reflected as: Junior School student mainly at the Level 1 or 2; Senior One students mainly at the Level 3 or 4;Senior Two students mainly at the Level 5.The study suggested that we can set up appropriate cognitive tasks according to the different content about the curriculum arrangement and teaching of this theme so that we can build a ladder according to the difficulty increased gradually from the shallower to the deeper so as to adapt to the current cognitive level of the students and to promote the level of understanding smoothly.