• Journal of The Korean Association For Science Education
• /
• v.38 no.1
• /
• pp.43-55
• /
• 2018

In this study, we investigated high school students' analogy generating processes using the think-aloud method. Twelve high school students in Seoul participated in this study. The students were asked to generate analogies on ionic bonding and were also interviewed after their activities. Their activities and interviews were recorded and videotaped. After classifying the analogy generating processes into the three stages-encoding, exploring sources, and mapping, several process components were identified. The analyses of the results indicated that they checked the target concept given and selected one for a salient attribute among many attributes of the target concept at the stage of encoding. After selecting the salient attribute, they translated the salient attribute that is a scientific term into an everyday term, which is named as 'extracting salient similarities.' At the stage of exploring sources, they chose the sources based on salient similarities and chose the final source through circular processes, which included the process components of 'evaluating the sources' and 'discarding the sources.' At the final stage, they added the attributes to analogs and mapping them to the attributes of the target concept, which is named as 'mapping shared attributes.' There were some cases that 'mapping shared attributes' appeared after they specified the situation of analogs or assumed new situation, which is named as 'specifying the situations.' Some students recognized unshared attributes in their analogs.

• Journal of Korean Elementary Science Education
• /
• v.37 no.2
• /
• pp.161-172
• /
• 2018

This study investigated the changes in representation on analogies that elementary science-gifted students generated by using Algodoo program to explain the electric current. After the students were taught about the 'components in circuit and their function' and 'electric current' with teacher centered analogy and PhET program for 4 class hours, they generated analogies to the electric circuit. Then they compared the similarity between generated analogy and target concept and matched it to the target concept. The result revealed that the battery, light bulb, and electric wire were changed according to the change of representations on free electrons. And they generated more proper analogies reflected the target concept when represented the free electrons by the circular particles than the water. From these results, we can say that generating analogy using Algodoo program is the effective education activity to help students understand abstract concept by visualizing it more easily and simply.

• Journal of The Korean Association For Science Education
• /
• v.38 no.4
• /
• pp.587-598
• /
• 2018

In this study, we investigated the characteristics of pre-service science teachers' curriculum design for lessons using self-generated analogy. Three pre-service science teachers at a college of education in Seoul participated in this study. After a workshop on lessons using self-generated analogy, they planned and demonstrated lessons. All of the teaching-learning materials were collected, and their lessons were observed and videotaped. Semi-structured interviews were also conducted before and after their lessons. The characteristics of lessons using self-generated analogy were analyzed in the perspectives of PCK. The analyses of the results revealed that they used various strategies to promote students' generating analogies. They lacked understanding of the stages of the lessons and the role of teachers. Although all of them considered assessment, they used limited assessment methods and assessment dimensions. Some actively considered students' misconceptions, and specifically anticipated analogies that students could generate. They determined topics for lessons considering various aspects such as the level of self-generated analogy and the characteristics of scientific conceptions. On the bases of the results, we suggest some educational implications for pre-service science teacher education.

• Journal of The Korean Association For Science Education
• /
• v.30 no.5
• /
• pp.668-680
• /
• 2010

In this study, we investigated the characteristics, the mapping understanding, the mapping errors, and the perceptions of student-generated analogies on the separation of mixtures using the sizes of particles by elementary school students' approaches to learning. Fourth graders (N=92) were selected and administered with the tests on the approaches to learning, self-generating analogies, and perception of self-generating analogies. The results revealed that the meaningful learners made more analogies, especially structural/functional, enriched, and higher systematic ones than the rote learners. However, there were little difference in students' approaches to learning in the subcategories of representation (verbal, pictorial, and verbal/pictorial), artificiality (artificial and everyday), and abstraction (abstract and concrete). The meaningful learners had deeper understanding of the analogy and fewer mapping errors than the rote learners. In addition, the numbers of the shared attributes included in student-generated analogies and the scores of the mapping understanding of the meaningful learners were significantly higher than those of the rote learners. Many students, regardless of students' approaches to learning, had positive perceptions of the self-generating analogies in various cognitive and motivational aspects. However, they also point out the various difficulties in the self-generating analogies as their disadvantages. Educational implications of these findings are discussed.

• ETRI Journal
• /
• v.16 no.4
• /
• pp.13-25
• /
• 1995

We have derived a nonlinear spatiotemporal differential equation for space-charge fields from Kukhtarev’s material equations in a moving coordinate system and obtained the spatial subharmonic instability boundaries by using linear stability analysis. It is also found that there is an analogy between the temporal subharmonic and the spatial subharmonc instabilities in the sense that the governing differential equations describing the instability boundaries are formally identical. The experiments for generating spatial subharmonic waves are performed in a photorefractive $Bi_{12}SiO_{20}$ crystal by using conventional moving grating technique. The threshold detunings are experimentally determined and the results are compared with the theory.

• Magazine of the Korea Concrete Institute
• /
• v.6 no.1
• /
• pp.101-110
• /
• 1994

본 연구에서는 임의형상의 속의 찬 또는 중공 단면에 대한 비틀림 상수 및 전단응력 계산용 범용 프로그램 TORSION을 소개한다. Membrane Analogy로부터 차분법을 유도한 뒤 Successive Over Relaxation 방법을 사용하여 정해를 효과적으로 얻을 수 있었다. 사각단면 이외 단면의 경우, 경계조건을 전체 Boundary Mesh에 대하겨 계산 입력해야하는 번거러움을 해격하기 위하여 자동경계 생성기법을 사용하였다. 개발된 프로그램 TORSION을 사용한 Parametric 해석을 통하여 비교적 정확한 일반 중공단면용 비틀림상수 계산을 위한 개략식을 제안한후, 콘크리트 표준시방서에 제시된 방법과 비교하였다.

• Journal of Korean Elementary Science Education
• /
• v.28 no.3
• /
• pp.292-303
• /
• 2009

In this study, we investigated the characteristics of the analogies, the mapping understanding, and the mapping errors on saturated solution of scientifically-gifted and general elementary students. Fifth graders (n=60) at four scientifically-gifted education institutes in Seoul and/or Gyeonggi province and fifth graders (n=91) at three elementary schools in Seoul were selected and assigned to the scientifically-gifted group and the general group respectively. After the students of each group performed the experiment and were taught about the target concept in the first class, they administered the test on the self-generating analogies on the target concept in the second class. The results revealed that the students in the scientifically-gifted group made more analogies, especially verbal/pictorial, structural/functional, enriched, and higher systematic ones, and had deeper understanding of the analogy than those in the general group. The numbers of the shared attributes included in the student-generated analogies and the scores of the mapping understanding of the students in the scientifically-gifted group were significantly higher than those in the general group. The students in the scientifically-gifted group had fewer mapping errors than those in the general group. However, not a few students in the scientifically-gifted group had at least one mapping error. Educational implications of these findings are discussed.

• Journal of Korean Elementary Science Education
• /
• v.30 no.3
• /
• pp.305-314
• /
• 2011

In this study, the analogies on saturated solution generated by elementary school teachers were analyzed in their numbers, materials, and types aspects. The results were also compared with those of general and science-gifted elementary students. A test on the self-generating analogies on the target concept was administered to 111 elementary school teachers, 60 fifth graders at four science-gifted education institutes and 91 fifth graders at three elementary schools. The results revealed that the teachers made more analogies than the general and science-gifted students. In general, both the teachers and the students tended to make the analogies using the materials in family, riding, digestive, and school situations. However, there were a little difference between the teachers and the students in the cases of the analogies using other situations including body/physical activity. Similarly to the cases of the students, the teachers made more functional analogies than structural or structural/functional ones and did more concrete ones than abstract ones. However, they made more verbal, artificial, and enriched analogies than the students. They also made more highly systematic analogies than the general students, and did less ones than the science-gifted students. Educational implications of these findings are discussed.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.4
• /
• pp.789-798
• /
• 1989

A naphthalene sublimation technique based on the heat/mass transfer analogy is used to investigate the circumferential mass transfer from a circular cylinder in an approaching uniform shear flow. Experiments are performed in a wind tunnel (450*450m $m^{2}$ with a shear flow generator which is specially manufactured for generating variable shear rates(S). The effects of an approaching shear flow are correlated with mass transfer coefficients. It is found that the local mass transfer rate on a circular cylinder is characterized with the shear parameter $K^{d}$ defined as Sd/ $U^{c}$ , where d is the radius of cylinder and $U^{c}$ is the approaching velocity at the center of cylinder. The angle on the corresponding to minimum Sherwood number is approximately proportional to the shear parameter on an upper and down number is approximately proportional to the shear parameter on an upper and down circular cylinder (0< $K^{d}$ <0.132). Changes on the averaged mass transfer rate are not significant for small $K^{d}$ , which are slightly proportional to K$d^{2}$ but the local mass transfer rates are significantly changed with the approaching shear flow.