• Journal of the Korean Chemical Society
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• v.61 no.3
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• pp.112-121
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• 2017

The purpose of the study was to investigate the effect of explanation in conjunction with gravity and density on students' alternative conceptions for floating and sinking phenomena. The subjects were 140 students of 11th grade in 4 classes of a high school located in Gangwon Province. We divided them in two groups; comparison and experiment. The students of experiment group learned explanation in confection with gravity and density. The students of comparison group learned explanation of pressure as represented in physics textbook. ANCOVAs (analysis of covariance) were conducted using the pretest as a covariance. In items related to characters of matter, 2 items are not significant and only 1 item has significant small effect size (Hedges' g=0.327). In the change of alternative conceptions, there is no meaningful gap between two group. However, in items related to relative weights between object and water, the all items have significant effect sizes (0.286~0.502). In addition, frequency of experiment group's alternative conceptions related to pressure decreases considerably, but comparison group does not. Therefore, the explanation in conjunction with gravity and density suggested in this study can decrease students' alternative conceptions related to floating and sinking phenomena and increase scientific conceptions.

• Journal of The Korean Association For Science Education
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• v.40 no.6
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• pp.583-594
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• 2020

In this study, the existing concept of density has a limitation in providing the cause of phenomena, and the concept of buoyancy poses a problem because it has many misconceptions and requires an overly difficult concept to understand quantitative calculation, so we suggest an explaining method as process viewpoint introducing the principle of lever. The new method of explanation has been proposed using the lever as visual tool to reveal the gravity as the fundamental principle and process viewpoint. As a result, teachers stayed on many alternative concepts and less than half of the teachers were aware that density was related to gravity. In addition, they recognized it as matter viewpoints, but there is a meaningful conceptual change after intervention(p<.000). Also, they evaluated that the new method is better able to recognize the principle and process viewpoint than the existing description method. Through this, we can confirm the educational value of explaining method as process viewpoint introducing the principle of lever.

• Journal of the Korean Chemical Society
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• v.62 no.3
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• pp.226-234
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• 2018

In this study, the models described in the textbooks related to floating and sinking phenomena in the chemical domain were evaluated based on the aspect of nature related to the generation of models. To achieve this, we were targeting statement of textbooks from 7th curriculum to 2009 revised curriculum. Analysis of textbooks was performed for science of elementary school (total 2 textbooks) and science of middle school (total 21 textbooks) which dealt with these phenomena. According to the textbooks analysis, characteristics of statement way were (1) No description of the model's prerequisites, (2) Statement based matter viewpoint, (3) Lack of pattern principle, (4) Inadequacy of the case covered. Although the education about the model for the students should be preceded by the education related to the process of model creation rather than the activity using the model, the education about the nature of the model is insufficient. In order to solve this problem, we propose the model statement in textbooks and the development of the model evaluation tool related to model creation.

• Korean Journal of Cognitive Science
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• v.15 no.4
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• pp.31-47
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• 2004

This study was carried out to examine the development of physical knowledge in children. Eighty children aged 3- to 11-year-old and 16 adults were participated in this study. Participants' knowledge about failing, sliding and sinking/floating objects was investigated to understand what kind of knowledge they had, whether their knowledge was organized as theory and what was the nature of the developmental change in physical knowledge. Results showed that, for falling object task children of all age had correct knowledge about object's falling phenomena. However, there were age differences in children's understanding of the cause of object's falling. As the children's age decreased, the frequency of explanation referring to the absence of supper rather than the gravity as the cause of falling phenomena increased. For the sliding object task, children of all age could predict the motion of sliding object correctly. But only a few 9- and 11-year-old children could understand the effect of object weight and relations between gravity, frictional force and their interactions. Children under age 7 showed no evidence of possessing these knowledge. For sinking or floating object task, children of all age and even adults showed difficulties in understanding the sinking or float phenomena per se. For the cause of these phenomena although a few 9- and 11-year-old children referred to buoyancy as the cause, they had no correct knowledge about the buoyancy. This was also true for the adults. As a conclusion, the results of this study suggested that, not 3, but as young as 5-year-old children's physical knowledge exited as a form of naive theory in terms of their use as a causal devise in explaining the cause of object motion. However, even the theory of 9- and 11-year-old children was lack of the abstractness and coherence, which were also important characteristics of a theory. Finally, developmental change in physical knowledge proceeded toward more frequent and consistent use of physical knowledge as causal device and more abstract and coherently organized theory.