[[alternative]]Exploration of the Instruction Effects of Junior High School Students’ Pressure Concepts

[[abstract]]Exploration of the Instruction Effects of Junior High School Students’ Pressure Concepts Wu-hsun Lee National Taiwan Normal University Graduate Institute of Chemistry Abstract The particulate concept of gas is a more difficult conceptions for junior high school students, and the students have many misconceptions about it. The purposes of this study were to investigate junior high school students’ misconceptions of gas particles, and design some teaching materials relative to gas particles to evaluate the effects of teaching throughout the teaching model of learning cycle. Based on the learning interests and attitude evaluation, students’ interests and attitude for this teaching model and science learning were marshaled. The subjects were junior high school from Taipei County and I-Lan County students. There were 482 students in total. The instruments used in this study were as follows : (1)diagnostic test of gas particles, (2)teaching activities of learning cycle, (3)diagnostic test of conceptions applications, and (4)the learning interests and attitude scale. The main findings of the study were : (1) Students have many misconceptions about shapes, distribution, and weight of gas particles. 50% students considered that the shapes of gas particles would change owing to external operations, such as pressure or compressing, the change of space. In the aspect of the distributions of gas particles, 85% students didn’t possess the conception that gas would distribute uniformly in a closed container. They thought that gas particles would concentrate in some space as a result of compression or the change of space. In the aspect of the weight of gas particles, 42% students didn’t think that gas has any weight, and only 30% students could understand that gas has weight and the weight will not change. Students were in the opinions that pressure or compression, and the change of the shape of gas particles would affect the weight of the gas particles. (2) For the situation of compressing gases, the percentages of the students from grade 7 to 9 who could point out that the shapes of gas particles will not change were14.5%, 34.9%, and 41.1% respectively. The percentages of the students from grade 7 to 9 who could point out that gas will distribute uniformly were 8.2%, 8.1%, and 12.6% respectively. The percentages of the students from grade 7 to 9 who could point out that gas particles have weight and their weight will not change were 21.4%, 21.5%, and 34.4% respectively. So it is obvious that there was an understanding of the shapes and the weight of gas particles increases as students’ age. For the distribution conceptions, students didn’t have the conception that gas will distribute uniformly in a closed space, except for the students of grade 9. (3) A marked difference obtained from comparing the responses in the pretest and the posttest was that the teaching model could assist students to understand the conceptions of the shapes and the weight of gas particles. But for the conceptions of uniform distribution of gas, it was not that helpful. For instance, the percentages of the correct responses of posttest for the conceptions of gas shape and gas distribution of students from grade 7 to 9 were 78.3%, 80.0%, 87.6%, and 55.3%, 54.3%, 73.1% respectively. (4) Most students assumed a positive attitude toward this teaching model. 80% students considered that the teaching model was vivid and vigorous, and felt that the natural science is no longer difficult. For teaching the concept of gas particles, we think that the teaching model can help students to learn the gas particle concept.