The Expressive Evaluation Of High School Student’s Scientific Explanation Ability To Chemical Concepts Based On PTA

Scientific explanation ablility has become one of the essential skills and literacies necessary for high school students to study science subjects today.As the cornerstone of the body of knowledge in chemistry,chemical concepts are a disciplinary tool that needs to be continuously understood,mastered and applied throughout the study of chemistry.Based on existing research on scientific explanation,this study aims to understand the comprehensive level of high school students’ scientific explanation ability to chemical concepts with the help of a comprehensive assessment approach of expressive assessment,to explore initially how to evaluate high school students’ scientific explanation ability to chemical concepts,and to further promote the overall and harmonious development of students’ scientific explanation ability to chemical concepts through assessment feedback.Based on constructivist theory,multiple intelligences theory and contextual learning theory,the author conducted a study on the performance evaluation of high school students’ scientific explanation ability to chemical concepts by using a combination of literature research method,interview method,questionnaire survey method and classroom observation method.Firstly,based on the PTA theory,a set of indexes was established to evaluate the ability of high school students to explain chemistry concepts scientifically,and two basic elements,"CER framework writing ability" and "metacognitive ability",were classified.The two basic elements are "CER framework writing ability" and "metacognitive ability",and the first level indicators consisting of "statement","evidence","reasoning" and "metacognition" are proposed.and further deconstructs them into "acquisition","transfer","comprehension","use" and"description".use","description","logic","metacognitive knowledge","metacognitive monitoring " 8 secondary indicators.Then,under the guidance of the expert survey method,the weights of the indicators were determined and scores were assigned to them.The internal consistency of the test questions was analysed using a small sample.Finally,a study was carried out with students from four classes,namely classes 4,8,20 and 21,in H senior school.The study showed that the assessment of high school students’ ability to explain chemistry concepts scientifically could be achieved using the PTA scale method with good results.In general,high school students’ ability to explain chemical concepts scientifically is at an average level;the level of scientific explanation ability is almost the same between different difficulty concepts;students’ metacognitive ability is poor;students are lacking in the five areas of acquisition,use,logic,metacognitive knowledge,and metacognitive monitoring,which can be implemented in future chemistry classroom teaching in a more targeted way.In response to the findings of the study,the following recommendations are made:(1)teachers help students understand the standard attributes of chemical concepts with the help of case studies when teaching;(2)teachers guide students to use the concepts to justify a real situation when teaching;(3)teachers set up more student assessment sessions when teaching.