The purpose of this study was to analyze the structural model of causal effects of students' variables on science process skills. Student characteristics investigated in the study included attitude related to the science, logical thinking ability, scientific experiences, cognitive style. Covariance structural modeling procedures were used to test causal inferences about hypothesized relationships. The sample consisted of 319 6th grade students and 321 8th grade students in Seoul City, Korea. Five instruments were used in the study, TSPS(test of science process skills), GALT(group assessment of logical thinking), CEFT(children embedded figures test), questionnaire of attitude related to the science, questionnaire of scientific experience. For statistical analysis, the study adopted the structural equation modeling with LlSREL, a computer statistical program developed by J reskog and S rbom. Major findings of the study are as follows:1) Logical thinking ability has a most strong direct effect on science process skills. 2) The structural coefficient of scientific experience influence on attitude related to the science has the greatest direct one than the others in the covariance structural model. According to the results of this study, it is very importance that various scientific experiences, particularly hands-on activity, should be offer to students to improve science process skills. Also, understanding the relationships of student variable to science process skills will be helpful to decision making on the part of curriculum developers, science teachers and researchers.

Students' protocols obtained from think-aloud interviews were analyzed in the aspects of the success at first two problem-solving stages (understanding and planning), the time to complete a problem, the time at each problem-solving stage, the number of transition, and the transition rate. These were compared in the aspects of the context of problem, the success in solving problem, students' logical reasoning ability, spatial ability, and learning approach. The results were as follows:1. Students tended to spend more time in everyday contexts than in scientific contexts, especially at the stages of understanding and reviewing. The transition rate during solving a problem in everyday contexts was greater than that in scientific contexts. 2. Unsuccessful students spent more time at the stage of understanding, but successful students spent more time at the stage of planning. 3. Students' logical reasoning ability, as measured with the Group Assessment of Logical Thinking, was significantly correlated with the success in solving problem. Concrete-operational students spent more time in completing a problem, especially understanding the problem. 4. Students' spatial ability, as measured with the Purdue Visualization of Rotations Test and the Find A Shape Puzzle, was significantly correlated with their abilities to understand a problem and to plan for its solution. 5. Students' learning approach, as measured with the Questionnaire on Approaches to Learning and Studying, was not significantly correlated with the success in solving problem. However, the students in deep approach had more transitions and greater transition rates than the students in surface approach.

Many middle school students have difficulty in understanding biological concepts because too many concepts are presented in the textbook compared to limited school hours. So, it is necessary to select concepts which are indispensable. The purpose of this study is to select key concepts in the unit 'The Continuity of Life' by surveying students' and teachers' cognition on the concepts. In this study, 78 concepts were extracted from 'Science 3', unit II 'The Continuity of Life'. To survey how students and teachers think the concepts, Likert type questionnaires were made. 300 third grade middle school students and 34 biology teachers were selected by random sampling and the questionnaires were applied. The following results were obtained:1. Students thought 59 concepts out of 78 were important and the mean score of important level of the concepts was 3.60. Students thought 26 concepts out of 78 were difficult and the mean score of diffculty level'of the concepts was 3.26. The more they think the concepts important, the more they think them difficult (r=0.7462, p<0.001). 2. Teachers thought 55 concepts out of 78 were important and the mean score of important level of the concepts was 3.82. Teachers thought 33 concepts out of 78 were difficult and the mean score of diffculty level of the concepts was 3.31. The more they think the concepts important, the more they think them difficult (r=0.6138, p<0.001). 3. The selected concepts were considered more important by teachers than by students(t=2.0150, p<0.05). However, there was no significant difference in evaluating the difficulty level of the concepts(t=0.7327, p>0.05). 4. It was found that students have difficulty in understanding concepts when they are presented in the textbook to require formal preparation than concrete preperation(t=2.6612, p<0.05).

One class of grade 7 was chosen as a control group, and the other as an experimental group. The control group watched only a film of motion in weightless situation, but the experimental group had a contrastive discussion before watching the film. In pretest, pupils were given contrasted views between the pre-Galilean and post-Galilean about falling and horizontal motion of bodies, and asked to choose one from two points of view and to write the reason why they choose it. After the pretest, control group students watched the same film as the experimental group did. On the falling problem, the control group ignored the contents of the film or regarded related contents as not related contents. However, through the contrastive discussion, experimental group pupils reconstructed their past vague ideas and noticed the cause of falling which was not perceived by the control group. On the horizontal motion, some in the control group agreed with post-Galilean view points after watching the film. Some of the pupils in the experimental group agreed with the post-Galilean viewpoint after performing the contrastive discussion. However, most of them agreed after watching the film. So we can conclude that the contrastive discussion which helped students to reconstruct their ideas made the difference between the two groups.

The purpose of this study was to investigate the instructional effects of a problem solving model on students' achievement, science process skills, and perceptions of science activities. The problem solving model was developed on the basis of the SSCS (Search, Solve, Create, Share) problem solving model while considering Korean educational situations under a national curriculum. The model developed is composed of 4 stages; identify, solve, create, and share. In this research, the treatment and control groups (6 classes) were selected from a middle school in Seoul and taught about the separation of mixture for four weeks. Prior to instruction, the Group Assessment of Logical Thinking and the Learning Approach Questionnaire were administered, and their scores were used as covariate and blocking variable, respectively. During instruction, classroom observations for each group were conducted with a researcher-made checklist. Immediately following the instructions, students' achievement, science process skills, and perceptions of science activities were measured by a researcher-made achievement test, the Middle Grades Integrated Science Process Skills Test(MIPT), and the Perceptions of Science Activities Questionnaire, respectively. The results indicated that students in the treatment group achieved significantly better than those in the control group. Although students in the treatment group were found to use more science process skills correctly during their science activities, the MIPT scores of the treatment group were not significantly higher than those of the control group. No interaction with students' learning approach was found for both students' achievement and science process skills. On the questionnaire of students' perceptions of science activities, the treatment group showed more positive perceptions and interest than the control group. Educational implications are discussed.

Experiments done in traditional physics laboratories have been criticized for giving too detailed instruction so that student could follow the experimental procedure without understanding. This type of experiment is often called "cookbook experiment." Cookbook experiment was known to be little help to understand the physics concepts and to increase student interest. To solve these problems with traditional cookbook experiment, non-directive introductory physics laboratory was designed and tried with the freshmen of Department of Physics Education of Seoul National University. Non-directive laboratory was characterized by the lack of step by step instruction for students to follow. The instruction students received consisted of the goal of experiment, a short introduction, and a list of suggested materials to be used. Student designed the experimental procedure and decided what material they wanted to use. One group submitted one lab report as a group to encourage cooperation among students. Lab report could be written in any form students wanted and no penalty point was given to poor data or inappropriate theory, etc to encourage taking risks. Penalty points were given if the students did not get involved during class hours. Student received extra point for being creative and / or working hard. Teaching assistants used Socratic dialogue in helping students to find their own way instead of explaining what they had to do. Students' interest about the non-directive experiment was studies at the of the semester. A questionnaire was made for students to answer. The questionnaire consisted of four categories, the equipment and the laboratory, the experimental procedure, the lab report, and teaching assistant. For each category, student were asked to explain the differences from other laboratory classes, features they liked and the reasons why they do, features they did not like and why they did not. At the end of the questionnaire, students were asked what hey wanted to change and what they did not. They also could put any opinion they had other than the questions asked. Student overall opinion was very positive. All the students said they liked the lack of detailed experimental procedure because it gave them the feeling of achievement, made them feel challenged and think in more diverse and creative ways. Students liked the lab report because group report forced them to discuss more and the free form lab report helped them to focus on the what they did. Student responses about the teaching assistant was also positive but not as enthusiastic as the experimental procedure or lab report. However students recognised that the role of the teaching assistant was as a guide, a supporter, or a facilitator.

The purpose of this study is to develop a valid and reliable instrument, applicable to high school Earth Science class experiment. In advance of developing items, I was selected 14 inquiry process skills and specified evaluative objectives for each of them to develop scales and criteria for them. I developed 28 evaluation items for 5 experiment subjects among those of high school Earth Science class. The first field trial was performed a sample of 5 high school students, and the second one using a sample of 25 high school students. The results are as follows. (1) The content validity and reliability(Cronbach $\alpha$) of the developed items were 82.7% and .86, respectively, the developed instrument in this study is considered valid and reliable. (2) The average difficulty index was .69 and the discrimination index was .30. (3) Answer sheets based on the reported results were rated 5 teachers and Inter-rater Reliabilitiy and Inter-rater Consistency were analyzed, its indices were .80 and .76, respectively. (4) The developed items show a low coefficient of .45 with TESIS, a set of paper-and-pencil test items developed by Lee, Hang-Ro(1991). That the experiment assessment is solely subject to the rater's viewpoint has been one of the major problems raised concerning the matter. This research, however, shows that a set of more specified scales and criteria for the evaluation will make it more valid, reliable and efficient.

The purpose of this study was to determine the strategies that middle school students used in solving problems concerning density and solubility. These were compared in the aspects of problem contexts for 42 students of varying logical reasoning ability, spatial ability, and learning approach. A coding scheme used consists of five categories: reading & organization, production, errors, evaluation, and strategy. Students' protocols were analyzed after intercoder agreement had been established to be .95. The results were as follows: 1. Students had more difficulties in reading and organizing the problems in everyday contexts than in scientific contexts. Students at the concrete-operational stage and / or surface approach were more likely to have difficulties in reading and organizing the problems than those at the formal-operational stage and / or deep approach. 2. Students tended to split up the solubility problems into sub-problems and to solve the density problem in everyday contexts in random manner. These were significantly correlated with the test scores concerning logical reasoning ability, spatial ability, and learning approach at the .1 level of significance. 3. Major errors in solving the density problems were to disregard the given information or generated and to use inappropriate information. Many errors in solving the solubility problems were found to be executive errors. The strategy to use the information given appropriately was positively related to students' logical reasoning ability, spatial ability, and learning approach. 4. More evaluation strategies were found in everyday contexts. Their strategies to grasp the meaning of answers and to check the math were significantly related to students' logical reasoning ability. 5. Students used the random trial-and-error strategy more than the systematic strategy and the systematic trial-and-error strategy, especially in everyday contexts. The strategies used by the students were significantly related to students' logical reasoning ability, spatial ability, and learning approach.

The field is a good learning environment that offers many opportunities. Status of conducting field trip in the middle and high school was investigated As a result, there was few teachers who disagree that a course in science should include learning in the field. Yet, on practical side, teachers who used to conduct the field trip over once a year in science class appeared to be about 23% only. Most of schools conducting field trips hadn't well-planned program for instructional activities. Many of teachers appealed that they should not get release time for conducting an extended field experiences, and that they could not obtained good information in relation to the contents, the methods and strategies of field activities. It says that a good field trip needs administrative and financial surport, many informations, and the teacher's exertion.

The purpose of this study is to develop a test of earth science inquiry abilities using structured items. To develop a more valid and reliable instrument factual data was used, and most of the previous studies regarding inquiry teaching method and inquiry evaluation were consulted. The model developed in this study is composed of 5 stages; recognizing problems and generating hypotheses, designing inquiry, pursuiting inquiry, interpreting data, and drawing conclusion. Also, in this study 10 science inquiry abilities; recognizing problems, generating hypotheses, controlling variables, designing experiments, performing experiments, transforming data, inferencing, predicting, conclusing, and generalizing were clearly defined. The test developed in the study, Test of Earth Science Inquiry Abilities, includes 25 multiple-choice (five-choice) items and requires testing time of 50 minutes. The content validity of items, objectivity of scoring keys and clarity of items were checked by 7 experienced specialists in science education and earth science. The developed test were investigated and revised through three field tests. According to the results of the third field trial, test reliability (Cronbach $\alpha$) was 0.62, difficulty index was 0.54 and index of discrimination was 0.35. Also, the developed Test of Earth Science Inquiry Abilities showed a correlation coefficient of 0.53 with TIPS. Therefore, the development of Test of Earth Science Inquiry Abilities using structured items satisfied the reliability and validity requirements for general assessment instruments for students' earth science inquiry abilities.

The purpose of this study was to identify the preferable learning strategies in science learning and to find out the relationship between these strategies and scientific achievement of students in the secondary school. The learning strategies were tested with two categories, self-focused and work-focused learning. The four types of learning strategies in science learning were analyzed, and they were named to organization, monitoring, elaboration and memorization strategies, which were defined by GSSS test. In the self-focused learning, the organization and monitoring strategies were preferred to the elaboration and memorization strategies. Middle school students had a preference for memorization strategy (p=0.000), whereas high school students had a preference for monitoring strategy (p=0.015). In the case of organization strategy, female groups were preferable to male groups (p=0.027). In the second form of learning types, work-focused learning, the memorization strategy was the same preference as organization and monitoring strategies in the secondary school students, especially the male groups of high school students. The preference of elaboration strategy was relative lower compared with that of self-focused learning type. Middle school students had a preference for monitoring strategy (p=0.001), whereas high school students had a preference for elaboration strategy (p=0.001). The difference of each preference between male and female groups was not shown. From the analysis of correlation between learning strategy and scientific achievement, it showed that the monitoring strategy was commonly correlated with scientific achievement. In the self-focused learning, elaboration and organization strategies were correlated with scientific achievement in high school students (p<0.05). In the work-focused learning, memorization strategy was correlated with scientific achievement in middle school students, especially in male groups (p<0.05).