• Journal of the Korean earth science society
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• v.45 no.5
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• pp.469-481
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• 2024

This study investigates how the middle school science curriculum influences conceptual changes among students regarding the direction of atmospheric pressure. To achieve this, a conceptual assessment based on pressure-related learning content from middle school grades one and three was administered to grade three students. The analysis revealed that despite having relatively correct concepts about atmospheric pressure and its direction related to molecular motion within containers learned in middle school grade 1 science, many students developed misconceptions that atmospheric pressure acts downward, as they learned Torricelli's experiment in middle school grade 3 science. These findings suggest that the organization of the curriculum and textbook content can significantly influence students' conceptual changes regarding atmospheric pressure. Therefore, when describing Torricelli's experiment in middle school science textbooks, it is proposed to emphasize not only the perspective of weight or one-directional action but also clarify the concept from grade 1 science that atmospheric pressure can act in all directions. Such efforts are deemed beneficial for the internalization and deep understanding of scientific concepts among students. Furthermore, educators who recognize these misconceptions in advance and design instructional models can preemptively minimize learners' cognitive conflicts and confusion. Additionally, the systematic development of strategies and guidelines by responsible institutions is necessary to ensure that accumulated research findings on misconceptions and textbook analysis are reflected in textbook content.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.194-201
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• 1996

A series of experiments to analyse and to compare performance of various types of mini-sprinkler was carried out. Twelve kinds of the sprinkler, which have various sizes of nozzle orifice diameter and structures of spreader, were selected to be tested. Flow (water sprinkling) rate and sprinkling intensity pattern from a sprinkler were measured as a first part of this study, and the results are as follows. Sprinkler flow rate of various sizes of nozzle orifice and applied water pressures could be predicted by Torricelli's theorem. Discharge coefficients of the Torricelli's theorem for the sprinkler nozzle of various sizes were determined by the experiment as 0.90- 0.95, 0.80-0.82 and 0.76-0.79 for 0.8, 1.2 and 1.6 mm of nozzle orifice diameter, respectively. Experiments on sprinkling intensity pattern resulted that nozzle orifice diameter and applied water pressure are major variables for uniformity of the sprinkling intensity. More uniform sprinklering patterns were noted with smaller nozzle orifice diameter of a sprinkler and at lower sprinkling pressure. Besides the variables, structure of spreader of a sprinkler is also an important variable for the uniformity of sprinkling intensity.