• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.10 s.253
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• pp.982-986
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• 2006

It is well known that the surface tension forces can make a particle denser than water float when the size of the particle is of the order of 1 mm. This is deeply related to the basic mechanism enabling small insects to wander around on the pond surface and also to a newly emerging technology of self-assembly using capillary forces. For the quantitative understanding of this effect, we experimentally study the maximum density of a cylinder that can float on water and how fast the cylinder sinks when the density exceeds the maximum value. We compare our experimental results with the theoretical prediction and find good agreement between them.

• Journal of Gifted/Talented Education
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• v.23 no.2
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• pp.237-256
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• 2013

The purpose of this study is to develop program that take a genuine interest in science and motivate students to keep up their study for science gifted children of start period. In this study, we develop and apply the program about sinking and floating for elementary science gifted students, and analyse degree of conceptual change. Students' prior knowledge is analysed for developing the program, and each step is settled about concept of density and buoyancy. Conceptests are arranged into step by step, and we apply the program to 26 science gifted students of 6th grade elementary school. We compare a percentage of correct answers of pre-test and post-test and evaluate Hake gain for analysis of degree of conceptual change. As a result, science gifted students' concepts are changed effectively into scientific concepts by program based on peer instruction for gifted students of start period. And they evaluate the program is novel and useful, also they can be motivated by the program.