• Journal of Korean Elementary Science Education
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• v.27 no.4
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• pp.385-398
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• 2008

The purpose of this study is to understand the effect of The Model of Phases of the Moon on conception changes for preservice teachers. The researcher interviewed two preservice teachers under the agreement with them on their participation in the research just before he performed a class using The New Model of Phases of the Moon. The post-interview with the same content as the pre-interview was preformed one month later. The main content of the interview is as follows; 'Explain the shape of the Moon by drawing it.', 'Explain the relative different position among the Sun, Earth, and Moon depending on phases of the Moon by drawing them.', 'What do you think of the cause of phases of the Moon?', 'Draw a picture to explain why we always see only one side of the moon.' The results of the research are as follows. First, the class with New Model of Phases of the Moon was able to perceive the relationship of Sun, Earth, and Moon in three-dimensions rather than in two-dimensions and it helped to change their misconception that the Moon's shadow causes the Moon's shape. Secondly, the class with New Model of Phases of the Moon helped preservice teachers understand better the different positional relationships among the Sun, Earth, and Moon depending on the Moon shapes. Third, the class adopting the New Model of Phases of the Moon help preservice teachers form scientific conceptions on the causes of phase change of the Moon. Fourth, the class with the New Model of Phases of the Moon is not appropriate for explaining the reason why only one face of the Moon is seen. Based upon the results above, the researcher realized the limitation of this model and suggested that this model would help learners understand phase change of the Moon and increase space perception ability.

• Journal of The Korean Association For Science Education
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• v.29 no.8
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• pp.874-885
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• 2009

The purpose of this study is to analyze illustrations, contents, and experiments in 6 kinds of science textbook from the 9th grade covering the phases of the Moon (on the phases of the Moon in six 9th grade science textbook) and to suggest coherent and effective contents and frame of the science textbook. Hence, the researcher decided the study problem. The study problems are as follows; 'Are the illustrations in the science textbook presented to help understand the phases of the Moon depending on the position of the observer?', 'Does the contents of the book clearly mention the phases of the Moon?', 'Can students understand the phases of the Moon through the experiments in the science textbook?', 'Do illustrations, contents, and experiment of the science textbook consistently explain the phases of the Moon?'. 10 persons (9graduate students including the researcher) took part in this study. All things unanimously agreed upon by all participants were reflected in the results. The results are as follows: First, the universal observer's view point is mixed with the earth observer's view in the illustration of these science textbook regarding the phases of the Moon. Moreover, illustrations of some textbooks are presented with such words as 'sunrise', 'midnight' and consequently contain too much. Second, the contents of the science textbook concerning the phases of the Moon is not described clearly. In addition, they don't give clear and detailed explanations for the reason of these changes. Third, all of the textbooks, except one textbook, describe the experiment regarding the phases of the Moon with the earth observer's view point but don't specifically mention that the view point is that of the earth observer's view point. Fourth, illustrations, contents, and experiments in the science textbook don't coherently explain the phases of the Moon. In addition, it is confirmed through the process of the result analysis that the described contents in the science curriculum is not well constructed or logical.

• Journal of the Korean earth science society
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• v.27 no.4
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• pp.353-363
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• 2006

This study investigates how the lunar phases drawing module-applied instruction affects high school students' conceptual changes of the lunar phases. 46 juniors in a high school were given the module instruction on drawing the lunar phases, and then interviews were conducted to verify conceptual changes in subjects' recognition structures. The types of students' misconceptions of the lunar phases change before the instruction were as follows. Type S is that the Earth's shadow covers the moon. Type SR is that one has both misconception of Type S and a scientific concept at the same time according to the positional relationships. The scientific concept means that an observer sees a moon's part which reflects sunlight. Type SB is that the Earth's shadow covers the moon or the moon can be seen or not by the background's brightness according to the positional relationships. The last Type SRB includes all three above-mentioned types, and it explains the lunar phases at each position. As a result of the module-based instruction, 26 out of 36 subjects built up the scientific concept and 10 students did not. 7 out of the 11 Type S and 3 out of the 17 Type SR students did not, either. Especially, type S students did not change their preconception that the phases of moon change were done by the earth's shadow. Here, their preconception is too much strong; as they solve problems, their preconception is more beneficial, comparing to the method which it is presented from the module. This fact supports that it is difficult for students to discard preconception.

• Journal of The Korean Association For Science Education
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• v.16 no.1
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• pp.61-76
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• 1996

The purpose of this study was to apply the instructional strategies for conceptual change prescribed by Posner et al(1982) to the astronomic content domain taught in the elementary and middle school and to analyze the characteristics of students' knowledge revealed in the test before, during and after the instruction. Also, it was to investigate the intercorrelation of cognitive levels, spatial ability and science achievement. The major findings of this study are as follows: 1. Students had a great variety of misconceptions related to the motion of the moon before the instruction, that is, the phases, the names of phases and the cause of changing phases by the moon's orbit about the earth, the moon's appearance and location at the given time, the relative positions of earth, moon and sun during a lunar eclipse, the cause that a full moon is not at the line of node once a month. In the analysis of students' responses concerning the cause of changing phases of the moon and a lunar eclipse, the results indicate that the great majority of students had rote learning rather than meaningful learning in the middle school. 2. Students' reponses during the instruction concerning the changing phases of the moon and the predictive knowledge about the motions of the earth and the moon were analyzed. 1) According to the results of the test given before and after experiment, after discussion, achievement score of the whole of subjects and groups in both preformal and formal cognitive levels appeared to increase linearly. 2) There was no statistically significant differences of achievement scores before and after experiment, after discussion between preformal group and formal group in cognitive levels. 3. Distribution of achievement scores according to the whole of subjects and groups in preformal and formal cognitive levels shows that there was a statistically significant difference between pretest and posttest. 4. Types of conceptual changes concerning the cause of changing phases of the moon that occurred from pretest to posttest were classified as accommodation, incomplete accommodation, assimilation, no change and no model. Six of the seven students starting instruction with alternative frameworks didn't sustain those alternative models throughout instruction. Five of these six students accommodated completely and the last one partially. Seventy-nine percentage of students taking instruction with fragmental models assimilated correct propositions at the end of the instruction. These results suggest that conceptual change model prescribed by Posner et al(1982) has promised the meaningful learning to students taking with fragmental models, especially in cases where students with misconception enter instruction. 5. High correlation between achievement score of simple-recall items and that of written items in pretest and posttest indicates that the higher students got the score in simple-recall items the better they also performed in written items. However, there was no statistically significant differences among cognitive levels, spatial ability and science achievement in the whole of subjects and groups according to the cognitive levels.

• Journal of the Korean Society of Earth Science Education
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• v.10 no.2
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• pp.161-172
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• 2017

The purpose of this study is to characterize students' conceptions on causes of the phases of the moon. For this purpose, students were given a worksheet for argumentative writing activity where in they need to choose the right answer between five statements and provide reasonable evidences about causes of the phases of the moon. Written arguments collected were used as analysis data and TAP(Toulmin's argument pattern) including conceptual analysis of TAP elements were utilized to figure out logical structures and subordinate conceptions. The result showed that students had various alternative concepts about causes of the phases of the moon and associated with celestial. Also 70.5% of subjects had incomplete argument structures, and error types of concepts had difference according to types of alternative concepts as well as TAP. These results mean that importance of checking students' preconceptions, need of scientific argumentation, and appropriate instructional strategies considering alternative conception types and fallacy types that students had.

• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.273-285
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• 2014

Purpose of this study is to analyze eye movements of pre-service teachers and elementary students about a visual material of the change on the lunar phases. Eye-Tracker was used for analysis for eye-fixation time and eye movement at the structure, behavior, function question on the visual material. The Results were as follows. First, the pre-service teacher checked the visual materials from a holistic perspective depending on the function questions and fixed eye-fixation on the moon of the behavior question concerned. On the contrary, elementary school student only checked function of the moon located in the upper part and eye-fixation focus was spread here and there regardless of the questions. Second, the pre-service teacher gazed at the sun, earth and moon in a consecutive order depending on the questions to identify their spatial relations and checked location of the moon related to the question. On the contrary, the elementary school student did not view relations between earth, sun and moon from a spatial perspective. These findings indicate that the pre-service teacher conjures up the mechanism of the change on the lunar phases and confirms it in visual materials by visualizing change on the lunar phase model from earth's point of view while the elementary school student fails to take advantage of visual materials to visualize it from earth's point of view.

• Journal of Korean Elementary Science Education
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• v.36 no.4
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• pp.447-460
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• 2017

This study asked preservice elementary teachers to conduct an inquiry of observing the moon, and analyzed the phenomena observed, difficulties experienced, and pedagogical suggestions by the preservice teachers. Participants were 31 undergraduate students enrolled in a science course in a university of education. As a part of the course, the preservice teachers observed the moon for about a month and completed personal journals which described the phenomena they observed, difficulties they experienced, and the pedagogical suggestions to help elementary students conduct the same inquiry activity. The analysis of the journals revealed that the preservice teachers observed the moon mostly during the evening or night and that they noticed lunar phases, directions, altitudes, and color and brightness more frequently than other phenomena. The preservice teachers experienced difficulties related to the observation time, lunar phases, directions, and altitudes, and, reflecting on their own experiences, suggested a variety of pedagogical ideas about these difficulties. The pedagogical suggestions by the preservice teachers also included how to help elementary students keep their interest and perform the moon observation for a rather long period of time. Implications for moon investigations in the elementary school science classroom and relevant research were discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.684-692
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• 2010

Based on the planar restricted three body problem formulation, optimized trajectories for the Earth-Moon transfer are obtained. Mixed impulsive and continuous thrust are assumed to be used, respectively, during the Earth departure and Earth-Moon transfer/Moon capture phases. The continuous, dynamic trajectory optimization problem is reformulated in the form of discrete optimization problem by using the method of direct transcription and collocation, and then is solved using the nonlinear programming software. Representative results show that the shape of optimized trajectory near the Earth departure and the Moon capture phases is dependent upon the relative weight between the impulsive and the continuous thrust.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.238-244
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• 2016

Copper electrodeposition on AZ91 Mg alloy was studied in views of preferential deposition on ${\alpha}$- or ${\beta}$- phases and how to achieve uniform deposition over the entire surface on ${\alpha}$- and ${\beta}$-phases in a cyanide solution. The inhomogeneous microstructure of AZ91 Mg alloy, particularly ${\alpha}$- and ${\beta}$-phases, was found to result in non-uniform deposition of zincate layer, preferential deposition of zincate on ${\beta}$-phases, which leads to non-uniform growth of copper layer during the following electrodeposition process. The preferential depositions of zincate can be attributed to higher cathodic polarizations on the ${\beta}$-phases. Pin-hole defects in the copper electrodeposit were observed at the center of large size ${\beta}$-phase particles which is ascribed to gas bubbles formed at the ${\beta}$-phases. The activation of AZ91 Mg alloy in hydrofluoric acid solution was used to obtain uniform growth of zincate layer on both the ${\alpha}$- and ${\beta}$-phases. By choosing an optimum activation time, a uniform zincate layer was obtained on the AZ91 Mg alloy surface and thereby uniform growth of copper was obtained in a cyanide copper electroplating solution.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.76-78
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• 1999

In this paper, the 2-phase excitation method is proposed to reduce vibration and noise. This excitation method produces reluctance torque by mutual action between two phases as well as conventional-reluctance torque due to two phases excitation at a time. The vibration and acoustic noise is reduced thought the sequential phase excitation. This is because that the scheme reduces abrupt change of excitation level by distributed. balanced excitation.