• Journal of The Korean Association For Science Education
• /
• v.24 no.6
• /
• pp.1094-1105
• /
• 2004

The effects of learning using Information Communication Technology(ICT) on the students' scientific inquiry ability and science-related affective characteristics were analyzed in Earth History and Crust Movement units of science textbook for eighth graders. For this study, two classes of middle school second students in Chung-nam were selected and taught for six week under different teaching methods. One class is the test class taught with ICT applied teaching materials and the other class is the control class instructed by a conventional method. One week before the experiment, both classes were given tests on scientific inquiry ability and science-related affective characteristics, and they were tested again after the experiment. The results of scientific inquiry test showed statistically meaningful differences in the experimental class and the control class. The experimental class showed statistically meaningful difference in scientific inquiry test. Science-related affective characteristics test showed no statistically meaningful difference in the experimental class. Among three scientific science-related affective characteristics, especially the one fields of interests showed statistically meaningful differences which suggest that learning using ICT has a positive effect on the expanding of students' science-related affective characteristics.

• Journal of the Mineralogical Society of Korea
• /
• v.21 no.1
• /
• pp.1-15
• /
• 2008

The Cretaceous Gajok gold-silver deposit within porphyry granite is located nearby the Cretaceous Pungam basin at the northeastern area in Republic of Korea. The Gajok gold-silver deposit is distinctively composed of a multiple-complex hydrothermal veins with comb, crustiform chalcedony quartz and vug textures, implying it was formed relatively shallower depth. The hypogene open-space filling veins could be divided into 5 paragenetic sequences, increasing tendency of Ag-rich electrum and Ag-phases with increasing paragenetic time. Electrum with high gold contents (${\sim}50$ atomic % Au) as well as sphalerite with high FeS contents (${\sim}6$ mole % FeS) are representative ore minerals in the middle stage. The late stage is characterized by silver-phase such like native silver and/or argentite, coexisting with Ag-rich electrum ($10{\sim}30$ atomic % Au) and Fe-poor sphalerite (< 1 mole % FeS). The ore-forming fluids evolution started at relatively high temperature and salinity (${\sim}360^{\circ}C$, ${\sim}7\;wt.%$ eq. NaCl) and were evolved by dilution and mixing mechanisms on the basis of fluid inclusion study. The gold-silver mineralization proceeded from ore-forming fluids containing greater amounts of less-evolved meteoric waters(${\delta}^{18}O$; $-0.6{\sim}-6.7\;%o$). These results imply that gold-silver mineralization of the Cretaceous Gaiok deposit formed at shallow-crustal level and could be categorized into low-sulfidation epithermal type, related to Cretaceous igneous activity.

• Korean Journal of Environmental Biology
• /
• v.17 no.1
• /
• pp.1-9
• /
• 1999

Numerous observations revealed strong evidence of increased middle ultraviolet radiation or UV-B (280 ~ 320 nm) at the earth's surface resulting from stratospheric ozone depletion. UV is the waveband of electromagnetic radiation which is strongly absorbed by nucleic acids and proteins, thus causing damage to living systems. It has been recorded in the East Sea, Korea that solar UV-B impinging on the ocean surface penetrates seawater to significant depths. Recent researches showed that exposure to UV-B for as short as 2h at the ambient level (2.0 Wm$^{-2}$) decreased macroalgal growth and photosynthesis and destroyed photosynthetic pigments. These may suggest that UV-B could be an important environmental factor to determine algal survival and distribution. Some adaptive mechanisms to protect macroalgae from UV-damage have been found, which include photoreactivation and formation of UV-absorbing pigments. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. The existence of UV-B absorbing pigments has been recognized in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp., which is likely to exert protective function for photosynthetic pigments inside the thalli from UV-damage. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half of the total biomass on the earth. UV-driven reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem. The ultimate impacts of increasing UV-B flux due to ozone destruction are still unknown, but the impression from UV studies made so far seems to highlight the importance of setting up long-term monitoring system for us to be able to predict and detect the onset of large -scale deterioration in aquatic ecosystem.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.5 no.1
• /
• pp.1-9
• /
• 2000

Vertical temperature distributions in muddy intertidal sediments near the Jebu Island on the west coast of Korea were obtained during the period of ebb tide which occurred in day time. The observations of mud temperature were made with thermistor embedded probe at 2cm interval for 18cm-layer of sediment for five different months of the year. Temporal changes in the vertical profile of the sediment temperature are strongly depend on the air temperature, the previous time of flood tide and the time of ebb tide. Heat exchanges in the surface layer (0-2 cm) in terms of magnitude and direction are greater than and opposite to those in the deeper sediment layer (8-12 cm), respectively and do not show any significant seasonal variations. In general, the surface layer gains heat while the deeper layer loses the heat. By using the 1-D diffusion equation temporal vertical profiles of the sediment temperature were obtained and were compared with the observed ones. The results show that in the sediment layer below 4 cm-depth the heat transport is predominantly by molecular diffusion. The average magnitude of heat flux into the sediment layer (0-18 cm) during the ebb tide when the mudflats were exposed in the middle of the day were between 4.1 and $28.9\;W/m^2$.

• Journal of Satellite, Information and Communications
• /
• v.2 no.1
• /
• pp.35-40
• /
• 2007

COSPAS-SARSAT is the search and rescue system for providing a distress alarm and a position identification using an international satellite and ground facilities. Aviators, mariners and land users worldwide are equipped with COSPAS-SARSAT distress beacons, which could help save their in emergency situations anywhere in the world. As the existing COSPAS-SARSAT system is generally operated by LEO(Low-altitude Earth Orbit) Satellite System, the time from the distress beacon to the rescue is more than 1 hour with average and the accuracy of the distress location is about 5 Km. Therefore, in order to overcome this problem, the development for the next generation SAR(search and rescue) system which uses the MEO(middle-altitude Earth Orbit) satellites is going on the Galileo project. EU is developing this project for the full operation capability in 2011, and this project will have SAR payloads and support to the Search and Rescue service-herein called SAR/Galileo. SAR/Galileo will have the performance of a few meter accuracy, within 10 minutes to rescue from reception of distress messages, and Return Link Service(from the SAR operator to the distress emitting beacon), thereby facilitating more efficient rescue operations and helping to reduce the rate of false alerts. As the disaster is larger every year, the ground station, MEOLUT for next generation ASR/Galileo is urgently needed for the lifesaving for the larger disaster, the research for beacon and the ground station such as MEOLUT for introducing the next generation SAR/Galileo in Korea is very timely and is important. This paper presents the procedures and the strategies for the participation, the area to develop reasonably, and the propulsion organization for developing the SAR/Galileo ground system in Korea.

• Journal of the Korean earth science society
• /
• v.38 no.2
• /
• pp.141-149
• /
• 2017

The geology of Saok island area in Jeollanam-do can be divided into 4 lithologic types: Jurassic granite, Cretaceous sedimentary rocks, acidic tuff and acidic dikes. In the Saok island area, dinosaur and web-footed bird footprints, arthropod trackway and silicified wood were found recently in the Cretaceous sedimentary rocks which composed of alternating light grey sandstone, shale and mudrock. The fossil-bearing sedimentary rock is overlain by an acidic tuff, and the sedimentary rock and acidic tuff are cut by acidic dykes. In order to constrain the depositional age of the Cretaceous sedimentary rocks in Saok island area, SHRIMP U-Pb zircon ages were determined in the tuffaceous sandstone and overlying acidic tuff. Zircon U-Pb ages of the sandstone and tuff are $83.58{\pm}0.86$ and $79.80{\pm}0.75Ma$, respectively, which belong to the Campanian of the Late Cretaceous. The U-Pb age of the acidic tuff indicates the eruption time of acidic tuff and thus the minimum age of the fossil-bearing sedimentary rocks in this area. Therefore, the formation age of the dinosaur and web-footed bird footprints can be constrained between 83.6 and 79.8 Ma.

• Journal of the Korean earth science society
• /
• v.29 no.3
• /
• pp.255-262
• /
• 2008

Late Cretaceous to early Tertiary paleostress was evaluated by analyzing the healed microcracks in the Cretaceous granite of the Goheung area, south Korea. Healed microcracks in five granite samples (GH-1, GH-3, GH-4, GH-5, GH-8) were investigated and measured according to direction. The directions of maximum horizontal principal stress in GH-1, GH-3, and GH-4 are dominantly $N60^{\circ}W\;and\;N70^{\circ}E,\;N20^{\circ}W\;and\;N50^{\circ}W$, while minor directions are N-S and $N30^{\circ}E$. In GH-5 and GH-8, $N40^{\circ}E\;and\;N10^{\circ}E$ are the most dominant directions, while $N40^{\circ}W$ is the minor direction. Thus overall, the most dominant directions of healed microcracks in the study area are oriented $N60^{\circ}W$, while minor directions are oriented $N20^{\circ}W,\;N20^{\circ}E\;and\;N70^{\circ}E$, essentially NE. Combining the paleostress results of this study with other studies, the direction of the maximum horizontal principal stress in the study area during the late Cretaceous to the early Tertiary should perhaps be changed WNW to NE. The reason for this is thought to be the complex tectonic movements which occurred in northeast Asia at that time.

• Journal of the Korean Society of Earth Science Education
• /
• v.12 no.1
• /
• pp.94-108
• /
• 2019

The purpose of this study was to develop the guided R & E program to improve science process skills of the science gifted students. First of all, we developed a guided R & E instructional models that enables students to conduct R & E through the third process from teacher-centered to student-centered, and developed guided R & E programs in accordance with the five-step process. As a result, it showed high average scores in the order of 'Hypothesis setting > Variable extraction > Derivation of inquiry problem > Conclusion derivation > Experimental design > Generalization > Evaluation > Data analysis > Data conversion'. In detail, among the nine evaluation factors, 'Derivation of inquiry problem, Variable extraction, Hypothesis setting, and Conclusion derivation' are at a high level, 'Experimental design' is at an average level, 'Data interpretation, Generalization, and Evaluation' were low level and 'Data conversion' was very low level. We hope that the guided R & E program reflected the elements of inquiry process will help students to improve their thinking ability and creative problem solving ability.

• Journal of the Korean Society of Earth Science Education
• /
• v.12 no.2
• /
• pp.119-130
• /
• 2019

The TIMSS assessment is conducted every four years, and Korean fourth grade cohort in TIMSS 2011 participated in TIMSS 2015 again as eighth graders, which produced the first achievement data of the cohort group of elementary and middle schools. In this study, in order to investigate the causes of the decline in Korean students' science achievement with grade changes from the fourth to the eighth grade, we analyzed educational context variables such as characteristics of students, teachers, and classroom instructions of the top 5 achievement countries participated in both TIMSS 2011 and TIMSS 2015. According to the results, students' sense of school belonging increased, whereas students' positive attitudes toward science teaching decreased with the grade change from the fourth to the eighth. As for the teacher characteristics, the teacher's professional development activity increased, and the teacher's confidence in science teaching showed similar tendency to the international average. Regarding classroom instruction characteristics, the frequency of inquiry-related science activities was highest at the fourth grade, and lower than the international average at the eighth grade. Based the results, we suggested implications for science teaching and learning as well as further studies including development of differentiated strategy by the school level to improve students' achievement, the necessity of converting into more student-engaging science classes, and the necessity of in-depth study on the teacher related educational contextual variables.

• Journal of the Korean earth science society
• /
• v.42 no.2
• /
• pp.221-244
• /
• 2021

To examine the limitations of the the Blosser's (1973) 'Question Category System for Science', which is mainly applied to research in science education in Korea, we analyzed 30 hours of class conversation in a small group program (for first-year middle school students) with a researcher participating as a teacher. When classified according to Blosser's (1973) classification system, distinguishing between 'open and closed questions' was difficult. Questions with the same content were classified into different types depending on their context, whereas some questions could not be classified appropriately. Additionally, higher-level questions (open questions) were not more effective than lower-level questions (closed questions) in improving students' thinking ability or participation in class. The questionnaire's effect differed depending on the information provided by the teacher before questioning, and in many cases, previous question influenced the next questions. However, in the science education questionnaire research based on Blosser's (1973) classification, which is mainly conducted in Korea, each individual question is classified according to the cognitive level, disregarding the influence of context and prior and subsequent questions and the quality of instructions is evaluated by the frequency of higher level questioning. The results of this study indicate that the method of evaluating instruction quality based on the frequency of high-level questioning, which is currently conducted in domestic science education inquiry research, should be avoided.