The Research Of Students’ Preconcepts Of Atoms And Molecules In Grade Nine And The Study On The Countermeasures Of Changing Them

Chemical concept plays an important part in chemical knowledge, the concept of"atoms" and "molecules" is a basic ability for grade nine students in junior middleschool to comprehend in order to learn chemical well. Before students acquirescientific concepts formally, their minds are not blank because they have beeninfluenced by common sense of life and other disciplines or knowledge, they alreadyhave preliminary understanding of the series concepts which can be defined asperceptions. These perceptions may be correct so they play positive role on thestudents’ science learning; but sometimes these perceptions may In complete or evenwrong and cause an adverse affection. The teachers should not skip students’perception sand teach directly in the teaching process, they should transform students’perceptions by proper teaching strategies.Students’ former concepts exist in their minds potentially; target teachingstrategies can be put forward only through discovering what perceptions Studentsalready have. This study were taken in a junior middle school in Jinchang City, GansuProvince, the former concepts of "atoms" and "molecules" in ninth grade studentslearning were probed through student interviews, teacher interviews and surveyquestionnaires, detailed data analysis were carried out by the researchers basing onthe research results, To manifest problems, appropriate teaching strategies weredeveloped in order to apply in teaching practice. The following strategies wereestablished: using Random Access Instruction mode; using cooperative learning tochange the original concept; using life experience to build classroom situation; usingthe history of chemistry to construct atomic concept; using models into themicroscopic world; using multimedia teaching to strengthen the visual impression.In junior middle school chemistry teaching, students’ former concepts are basisfor learning science concepts, they tend to understand concepts according to theirpersonal experiences. The study in go perceptions has important practical meanings inteaching, theoretical guidance and teaching reference for chemistry professors wouldbe hopefully provided by this study.