Junior High School Chemistry Different Vision Of Exploration And Change

Preconception is called as 'children's conception'/substitute conception', 'daily conception','individual conception' etc. There are two kinds of students' preconception: one is the opinion or conception about things and phenomenon that is formed by students according to daily experience during interacting with nature and society environment before they are educated formally. The other kind is formed in teaching practice after students begin to be educated formally at school. Some of the preconceptions are consistent with cognition and scientific conceptions, but others are not. These inconsistent opinions and conceptions are called alternative conception, which is similar to the misconception that we usually say. The two kinds of preconceptions are the same essentially. They both reflect the students' dependant on instinct and experience during their thinking process.The alternative conception is comprehensive, spontaneous, obstinate and concealed. It exits comprehensively in students of different levels, and together with common scientific conceptions. After adjusting and transforming, they can exit in the students' cognition structure, together with the consistent information they have received in class, and become some conceptions that are much more concealed and deeply-rooted. When facing some complex situations, they would be aroused. This phenomena exiting in students of different levels, is not easy to be found and corrected. These alternative conceptions have some unconstructive effects on the accepting, forming and developing of the students' scientific conceptions.According to the relating literatures, the international and Taiwan studies about alternative conception are much more. Conceptual change mainly in physics, biology, mathematics etc. Not only in quantity but also in quality, the international study about the preconception of students is not so advanced. And the study about the alternative conception changing in chemistry is mainly concentrated on senior middle school students. But the domestic research of learning psychology about the problem of students' preconception and changing in the correct and efficient teaching practice has just begun. And the study is mainly concentrated on investigating period.About 910 students of grade 2 and grade 3 students of junior high school wereinvestigated by using "questionnaire on chemistry preconception of junior high school students". Statistics data show that students have remarkable alternative conception at the aspect of substantial identity, burning, liquor, mass conservation and so on. This study shows that junior high school students of grade 2 have alternative conception because of shortage of perceptual knowledge, wrong ways of thinking, being affected by regular thinking passively and being interfered by correlative conception. Some studies indicates that junior high students' preconception of grade 3 may appear several circumstances in teaching.Not being affected by teaching; changing a little in order to prepare for the examination without the change of the original conception; daily conception being wrongly strengthened while being mistakenly used to explain current situation; daily conception being disordered and inconsistent because of being thought unreasonable, but reasonable scientific conception not being established. The reason that the preconception appears is: language, instinct, definition or veracity of original correlative knowledge, students' cognitive ability, experience of daily life, teacher/teaching material, knowledge of correlative subjects, social environment/ feeling/ motivation, etc. Shortage of perceptual knowledge is the main reason that grade 2 and 3 students of junior high school have got alternative conception.We have known which preconception is in student's mind, then how to change the preconception to scientific conception? First, we should choose examples or phenomenon pertinently and let students explain examples or phenomenon with their preconceptions, which make them produce collision on cogn...