[[alternative]]Investigating the Junior High School Students' Concepts Regarding Chemical Change by Means of Group Demonstration Test and with a Particle-model-simulation Instruction: The Production of Gas as an Example

[[abstract]]In daily life, it is full of chemical change. However, because of ordinary terms, direct judgment, and improper teaching, students have quite a lot of wrong recognition of these changes which are normal phenomenon. Taking the chemical change of producing gas for example, this research was aimed at investigating students’ recognition of correlated concepts by means of group demonstration test using self-designed experimental instrument and the problems of two-tier diagnostic test. Furthermore, by means of the experiment-manipulating observation and particle-model-simulation instruction, students could improve their concepts and changed their misconceptions concerning the chemical changes of gas production. The subjects including all the grades in the junior high school, were divided into the experimental group and the control group. There were totally 424 students. The main findings in this research were: 1.Most students were unclear about the definition of chemical changes, lack building up the concept of material, and were not good at distinguishing the variety of changes. Moreover, most students were unclear about the process of chemical changes, and unable to think the character of microscopic particles. Therefore, they held misconceptions of chemical changes. No matter in the microscopic or macroscopic view, students’ main misconceptions were “making something out of nothing” and “disappear out of the void”. 2.Comparing the difference in the recognition of the concepts of chemical change, students’ recognition of the most concepts was progressed while their grades were higher. It implies that the comprehension of chemical changes needs students’ mature ability of abstract thinking. 3.Comparing the improvement between the experimental and the control group before and after the instruction, it proved that the experiment-manipulating observation and particle-model-simulation instruction were significantly effective in understanding the process and the particle concepts of chemical changes. Moreover, in this research, it showed that there was much effective for the eight grade students. It means that by model instruction it had better effectiveness for helping the students who were developing their ability of abstract thinking.