• 제목/요약/키워드: the earth and moon

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An Analysis of 'The Phases of the Moon', Contents of 9th Grade Science Textbook (중학교 3학년 과학 교과서의 '달의 위상변화' 문제점 분석)

  • Chae, Dong-Hyun
    • 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.

Elementary School 5th Students' Understanding of the Illustrations on the Phase change of the Moon in Science Textbook of 2007 and 2009 Revised National Curriculum (2007과 2009 개정 과학교과서에 제시된 달의 위상 변화 삽화에 대한 초등학교 5학년 학생들의 이해)

  • Yang, Il-Ho;Kim, Jung-Yun;Lim, Sung-Man
    • Journal of the Korean Society of Earth Science Education
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    • v.8 no.1
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    • pp.56-65
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    • 2015
  • The purpose of this study is to investigate how elementary school student understands or students understand the illustrations on the phase change of the Moon in science textbook and to find out how textbook illustration helps students form the conception of the phase change of the Moon. To identify this purpose, we selected illustrations on the phase change of the Moon in the science textbook revised in 2007 and 2009 revised science textbook. For this study we selected and interviewed 20 students in the fifth grade. We integrated all data collected through interviews and created a transcription and a protocol and then, confirmed scientific conceptions related to the phase change of the Moon in students' illustration reading. The result are as followings: First, students read more scientific conceptions related to the phase change of the Moon in illustration of the 2009 revised science textbook which is presented with the universal observer's view point and the earth observer's view point. Second, students who find meaning in the various elements of the illustration and interpret with the integration of the various elements, get a lot of relevant information from illustration. All students have no differences recognizing the elements presented in illustration. But there are differences of contents of illustration reading depending on how students interpret the illustrations with integration of the various elements and if students cannot figure out the four scientific concepts needed to understand the phase change of the Moon, they ignore the information provided by illustration or analysis in their own way according to information provided by illustration. So misconception appears in this process.

An Analysis the Contents Related to a Subject 'Earth and Moon' from Elementary Science Textbooks of the 2009 Revised Curriculum and 2015 Revised Curriculum ('지구와 달' 주제와 관련된 초등학교 2009 개정 과학교과서와 2015 개정 과학교과서 내용 분석)

  • Lim, Cheonghwan;Chae, Donghyun
    • Journal of the Korean Society of Earth Science Education
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    • v.11 no.3
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    • pp.237-243
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    • 2018
  • The purpose of this study is to analyze the contents related to a subject 'Earth and Mooon' from elementary science textbooks of the 2009 revised curriculum and elementary science textbooks of the 2015 revised curriculum. For the research, the team selected and analyzed the contents of the 'Earth and Moon' unit in the elementary science textbooks of the 2009 revised curriculum and 2015 revised curriculum. As a result of the research, first, there has been no significant change in achievement standards of the curriculum as the science textbook revised from 2009 curriculum to 2015 curriculum. Second, the two curriculum did not differ much in specific textbook contents statement or development, but they showed much change in presentation of exploration activities in curriculum as well as the specific exploration activities presented in the textbooks. Third, compared to science textbooks of the 2009 revision the 2015 revision used more pictures and illustrations. Forth, there have been few changes related to experimental observation, but the activities to organize the unit in 2015 revision have been strengthened compared to the 2009 revision.

The Lateral Earth Pressure on Braced Cut Walls Considering Subsoil Condition in Korea (국내 지반조건을 고려한 흙막이 백제에 작용하는 토압)

  • Chae, Young-Su;Moon, Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 1994.09a
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    • pp.129-138
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    • 1994
  • It is well recognized that accurate analysis of lateral earth pressure is very signficant factor which determines the design amount of braced cut walls and braced systems. Many researchers, Peck, Terzaghi-Peck and so on, make a study about lateral earth pressure to act on the flexible walls. But these studies trouble accurate to multy layered systems like inland areas in Korea. This study is compared with the field messurement data to estimate the earth pressure distributions in multy layered areas and the empirical earth pressure distributions. The conclusions are as follows : At final excavation depth, the lateral earth pressure which messured by field instrument is smaller than the empirical earth pressure. (About 1.85~5.32 times). In the case of considering the soft rock layer to the final excavation depth, the messured earth pressure is safe to be compared with empirical earth pressure. The messured earth pressure distributions are like that the upper soil layer is small the middle soil layer is large, the rock mass layer is very small.

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A Parametric Study on Optimal Earth-Moon Transfer Trajectory Design Using Mixed Impulsive and Continuous Thrust (혼합 추력 방식의 지구-달 최적 전이궤적 설계인자에 따른 비교연구)

  • Lee, Dae-Ro;No, Tae-Soo;Lee, Ji-Marn;Jeon, Gyeong-Eon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.11
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    • pp.1021-1032
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    • 2011
  • This paper presents the results of a parametric study for the design of optimal Earth-Moon transfer trajectory using mixed impulsive and continuous thrust. Various types of the optimal Earth-Moon transfer trajectories were designed by adjusting the relative weight between the impulsive and the continuous thrust, and flight time. Two very different transfer trajectories can be obtained by different combination of design parameters. Furthermore, it was found that all thus designed trajectories permit the ballistic capture by the Moon gravity. Finally, the required thrust profiles are presented and analyzed in detail.