Tae-Hee Noh

The influence of students’ cognitive and motivational variables in respect of cognitive conflict and conceptual change

In this study, the relationships among students’ cognitive/motivational variables, cognitive conflict, and conceptual change were investigated. Subjects were 159 seventh graders in Korea. Tests regarding logical thinking ability, field dependence/independence (FDI), meaningful learning approach, failure tolerance, mastery goal orientation, and self‐efficacy were administered to examine students’ cognitive/motivational characteristics. A preconception test and a test of responses to discrepant event were also conducted to examine the degree of students’ cognitive conflict induced by a discrepant event. Computer‐assisted instruction, designed to change an undifferentiated weight‐density concept into a scientific density concept, was then provided to students as a conceptual change intervention. A conception test was administered as a post‐test. The results indicated that FDI was the only statistically significant variable correlated with the degree of cognitive conflict. A stepwise multiple regression analysis revealed that logical thinking ability, FDI, and failure tolerance were statistically significant predictors of the conception test scores. Educational implications are discussed.

FERROELECTRIC SWITCHING DYNAMICS AND PULSE-SWITCHING POLARIZATION MEASUREMENTS

ABSTRACT Pulse switching properties were studied in polycrystalline Pb(Zr,Ti)O3 capacitors to check a recently proposed nucleation limited switching (NLS) model, where very wide switching was observed. The backing-switching responses (P b) at the end of writing pulses were studied to understand the role of writing pulse together with switching polarization (Δ P). The P b+Δ P, with high enough write voltage, is almost independent of writing pulse width (t w), even though Δ P is observed to increase with increasing t w. From these results, it is concluded that the NLS dynamics are attributed to the switching and poling processes with external fields around coercive fields.

Perceived professional needs of Korean science teachers majoring in chemical education and their preferences for online and on‐site training

In this study, we investigated the perceived professional needs of Korean science teachers majoring in chemical education, and examined their preferences for online and on‐site inservice teacher training programmes. The results were also compared with those of preservice teachers. Participants were 120 secondary school teachers and 67 preservice teachers, whose majors were either chemical education or science education with emphasis in chemistry. A questionnaire consisting of a modified Science Teacher Inventory of Need and a section concerning respondents’ demographic information and their use of the Internet was administered. In contrast to previous studies, the perceived needs of Korean inservice and preservice teachers were found to be very strong in all 30 needs assessment items, and their prominent needs were from all seven categories. Preservice teachers indicated significantly greater needs than inservice teachers on several items. Korean teachers generally tended to prefer online inservice to traditional on‐site training programmes, although they still preferred on‐site types of programmes in areas such as conducting laboratory sessions and demonstrating manipulative skills. Preferences for online programmes tended to be stronger among preservice teachers than inservice teachers, and among non‐veteran teachers than in veteran teachers. Educational implications are discussed.

Pulsed laser deposition of Bi4Ti3O12 thin films and their anomalous imprint characteristics

Abstract Using La0.5Sr0.5CoO3(LSCO) or Pt film as a bottom electrode layer, epitaxial Bi4Ti3O12(BTO) thin films were deposited on MgO(001) substrates by pulsed laser deposition. X-ray diffraction patterns showed that the c-axes of BTO films are oriented normal to the substrate surface. Interestingly, an epitaxial Pt/BTO/Pt film showed a strongly preferred polarization state directed towards the top electrode in spite of the symmetric electrode configuration. The inprint state did not change significantly in the pulse test with DC bias. These anomalous behaviors suggest that the imprint characteristic is highly correlated with interfacial states between the electrodes and the BTO films. To understand space charge effects in the metal-ferroelectric contacts, imprint characteristics of the thin film capacitors with various top electrodes were investigated. Auger Electron Spectroscopy(AES) depth profile was measured, to check the possibility of a interdiffusion of the bottom electrode with the BTO layer. Inte...

An Exploration of the Factors Related with Preference for and Participation in Science-related Activities of Elementary School Student

In this study, we explored the factors related with preference for and participation in science-related activities of elementary school students. We developed a questionnaire to measure the characteristics of students such as motivation toward science learning, science aspiration, family science orientation, parental educational level and occupation, and the degrees of preference and participation of science-related activities. The questionnaire was administered to about 400 fourth graders in Seoul. The results revealed that the students with higher motivation toward science learning and/or science aspiration preferred and participated more in most activities. It was also found that parental educational level and occupation did not make an appreciable difference in preference and participation. The students who perceived their parents to be science-oriented, however, preferred and participated more in most activities. These results may offer practical implications for effective uses of both school and out-of-school science activities in elementary science education.

The Types of Interlanguage of Middle School Students in the Process of Learning Diastrophism

The purpose of this study is to explore the types of interlanguage that middle school students use in learning about the concept of diastrophism. Eighteen students from two classes in a middle school in Seoul participated in the study and each participant was interviewed four times. Data were analyzed in terms of semantic relations and thematic patterns. As a result, eight interlanguage types were identified and described, which are using everyday language as resources, combining scientific words with everyday words, conjugating scientific words imperfectly, and using semantic relations inappropriately. The implication of interlanguage for science learning and teaching is discussed.

[2+2] Heterodimers of methyl phenanthrene-9-carboxylate and benzene

Both syn- and anti-[2+2] heterodimers (1 and 2) of methyl phenanthrene-9-carboxylate (9-MP) and benzene were synthesized from 9-MP and cyclohexa-1,4-diene. Upon irradiation of 9-MP and excess methyl orthoformate of cis-cyclohexa-3,5-diene-1,2-diol followed by hydrolysis, the syn-[2+2] cycloadduct and also four cyclodimers of 9-MP were produced. Triplet-sensitized photocycloaddition followed by hydrolysis provided the anti-[2+2] cycloadduct. Dehydroxylation of the cycloadducts under mild conditions gave 1 and 2. In contrast to the previous reports on [2+2] dibenzenes and [2+2] heterodimers of acenaphthylenes and benzene, kinetic analysis of the thermolyses of 1 and 2 indicated that 1 was kinetically less stable than 2. Photodissociation of 1 and 2 were found to be adiabatic with efficiencies of 0.33 and 0.39. An explanation is provided for their thermoreversion and photoreversion.

Synthesis of 9-cyanophenanthrene–furan and –benzene cyclodimers and their reversion

In contrast to the previous report, the irradiation of 9-cyanophenanthrene (9-CP) and furan through a uranium filter yielded an anti-[2+2] adduct (1) as well as the syn-[2+2] cyclodimer (2) of 9-CP. A mechanistic study indicated that the photocycloaddition of furan occurred in the triplet state of 9-CP. The anti-[2+2] adduct (1) was prepared in the consumed yield of 69% by a photosensitized cycloaddition with Michler’s ketone. The anti-[2+2] cyclodimer (5) of 9-CP and benzene was synthesized by the triplet-sensitized photocycloaddition of a substituted cyclohexa-1,3-diene to 9-CP followed by dehydroxylation. The thermoreversion and photoreversion of 1 and 5 prepared were studied. The photodissociation of 1 and 5 was found to be adiabatic with the efficiencies of 0.11 and 0.33.

Features of Using Smart Devices in Socioscientific Issues Debate Classes

이 연구에서는 고등학생의 과학관련 사회쟁점(SSI) 수업에서 스마트 기기를 활용함으로써 나타나는 특징을 분석하였다. 경기도에 소재한 고등학교에 재학 중인 27명의 학생들을 대상으로 스마트 기기를 활용한 SSI 토론 수업을 진행하였다. 스마트 기기를 활용한 SSI 수업을 자료 탐색, 자료 공유, 자료 요약 및 정리, 교실 토론, 온라인 토론의 총 5단계로 구분하여 단계별 특징을 분석하였다. 연구 결과, 자료 탐색 단계에서 학생들은 각자의 지식과 관심을 반영하여 자기주도적으로 심층적인 자료를 수집하였으며, 자신이 이해하기 쉬운 형태의 자료를 선택하여 학습하였다. 자료 공유 단계에서는 온라인보다 오프라인에서의 공유가 활발하게 일어났으며, 공유 과정을 통해 수집한 근거의 구체성과 타당성 및 출처의 명확성이 향상되었다. 자료 요약 및 정리 단계에서 학생들은 스마트 기기보다는 종이에 자료를 정리하였으나, 대부분의 학생들은 토론 과정에서 정리한 자료를 제대로 활용하지 못하였다. 교실 토론 단계에서는 구체적 근거에 기반한 주장과 반박이 활발하게 이루어졌으며, 이는 토론에 대한 학생들의 흥미를 높여 적극적인 토론 참여로 이어졌다. 온라인 토론 단계에서는 학생들이 양측의 논거를 재정리하고 검토할 뿐 아니라, 교실 토론에서 소극적이었던 학생들의 토론 참여가 높아지는 것으로 나타났다. 이러한 연구 결과를 바탕으로 스마트 기기를 활용한 SSI 수업을 효과적으로 진행하기 위한 방안에 대해 논의하였다.

The Influences of Integrated Science Developed Under the 2009 Revised National Curriculum on Students` Views on Nature of Science and Science-Technology-Society Relationship, Interest in Science, and Science Aspiration

In this study, we investigated the influences of Integrated Science on the views of 10th graders with regards to the nature of science (NOS), STS, interest in science, and science aspiration, in order to explore the effects of Integrated Science developed under the 2009 Revised National Curriculum. Participants in this study were 214 10th graders in Seoul. The survey was administered at the beginning and at the end of the Integrated Science course. The analyses of the results revealed that there was no statistically significant difference in the scores of the pre-test and post-test on the NOS survey. However, the post-test scores of the tentativeness of scientific knowledge and the use of imagination, which are the sub-constructs of the NOS, were found to be significantly lower than the pre-test scores. There were no statistically significant differences in the frequencies of the responses to each item of the STS survey. The pre-test and post-test scores of the interest in science and the science aspiration were also not significantly different. The results indicated that Integrated Science did not have any impact on students` views on NOS, STS, interest in science, and science aspiration. Educational implications of these findings are discussed.