• 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 the Korean Society for Marine Environment & Energy
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• v.4 no.4
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• pp.21-31
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• 2001

When an oil-spilling accident occurs at sea, it is of the primary importance to predict the amount of oil leakage for the swift response and decision-making. The simplest method of oil-leakage estimation is based on the hydrostatic pressure balance between oil inside the tank and seawater outside of leakage hole, that is the so-called Torricelli equilibrium relation. However, there exists discrepancy between the reality and the Torricelli relation, since the latter is obtained from the quasi-steady treatment of Bernoulli equation ignoring viscous friction. A preliminary experiment has been performed to find out the oil-leaking speed and shape. Soy-bean oil inside the inner tank was ejected into water of the outer tank through four different leakage holes to record the amount of oil leakage. Furthermore, a CFD (Computational Fluid Dynamics) method was utilized to simulate the experimental situation. The Wavier-Stokes equations were solved for two-density flow of oil and water. VOF method was employed to capture the shape of their interface. It is found that the oil-leaking speed varies due to the frictional resistance of the leakage hole passage dependent on its aspect ratio. The Torricelli factor relating the speed predicted by using the hydrostatic balance and the real leakage speed is assessed. For the present experimental setup, Torricelli factors were in the range of 35%~55% depending on the aspect ratio of leakage holes. On the other hand, CFD results predicted that Torricelli factor could be 52% regardless of the aspect ratio of the leakage holes, when the frictional resistance of leakage hole passage was neglected.