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Volume 21, Issue 6  (2012)

Education: Theory & Practice:
A. Gendjova
Chemistry Education in Context. Challenges for Prospective Teachers

Full text: PDF (312 K)

807
Curriculum Matters:
M. Boycheva, R. Davidova
How to Develop Pupils' Cognitive Interest on the Basis of the Subject "Man & Nature: Structure and Life Processes of Organisms": In -Service Training of Teachers without Biological Education. I. [In B

Full text: PDF (286 K)

818
M.I. Stojanovska, V.M. Petrusevski, B.T. Soptrajanov
Addressing Students' Misconceptions Concerning Chemical Reactions and Symbolic Representations

Full text: PDF (585 K)

829
Teaching Efficiency:
I. Burovska. S. Tsakovski
Study of the Pupils' Performances (Fifth Grade) in the Subject "Man & Nature" [In Bulgarian]

Full text: PDF (660 K)

853
Foreign Educational Tradition:
M. Nur-E-Alam Siddiquee, H. Ikeda
Science Teachers' Views on Nature of Science: A Case of Bangladeshi Secondary Schools

Full text: PDF (593 K)

865
Advanced Science:
B. Adinew
Photochemistry of Turmeric: An Overview

Full text: PDF (539 K)

888
V. Simeonov
Ecotoxicology [In Bulgarian]

Full text: PDF (287 K)

898
Personalities in Science:
D. Klisurski
Dobri Lazarov - Chemist, Educator, Popularizer of Science [In Bulgarian]

Full text: PDF (579 K)

912
D. Klisurski
Elka Pencheva - Family Tradition and Own Achievements [In Bulgarian]

Full text: PDF (997 K)

916
History and Philosophy of Science:
A. Milchev
Alexei Scheludko and His Contribution to the Field of Electrocrystallization [In Bulgarian]

Full text: PDF (2955 K)

920
Archives:

Prof. Metodij Popov about Science and Scientific Activity (1920) [In Bulgarian]

Full text: PDF (1325 K)

939
Annual Content:

VOLUME 21, NUMBERS 1 - 6, 2012

Full text: PDF (269 K)

954
 

Khimiya, Volume 21, Issue 6(2012)

Khimiya. 21, 807- (2012) Author(s): A. Gendjova:

Abstract.One way to improve education is the use of different contexts of science as starting points for the development of scientific knowledge. In this paper some concepts as classroom context, science context, context-based approach in education, are examined. Different chemistry contexts, situations and areas are presented. Case study with 36 students is conducted in the period 2006-2011. It sought to identify the difficulties and challenges for prospective chemistry teachers in finding and using scientific context for designing education. Some problems related with training of students.

Keywords: chemistry education in context, prospective teachers, teacher training

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Khimiya. 21, 818- (2012) Author(s): M. Boycheva, R. Davidova:

Abstract.The aim of this study was to design learning and cognitive tasks which would be used for developing cognitive interests of the students to their primary biological education. The teachers trained are without a special biological education. The school subject is ???Man & Nature: Structure and Life Processes of Organisms. The proposed methodological constructions make no claim to be universal and should be used only as models which are subject to creative improvement or adaptation by the teacher according to the concrete peculiarities of the teaching process.

Keywords: pupils?? cognitive interest, school subject ???Man & Nature???, 6th grade

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Khimiya. 21, 829- (2012) Author(s): M.I. Stojanovska, V.M. Petrusevski, B.T. Soptrajanov:

Abstract.The purpose of the study was to investigate the ideas of students about some basic chemical concepts, such as dissolving, burning, structure of ionic substances, as well as reactions involving gases, external condition and limiting reagents. Also of interest was the way students understand and use symbolic representations in writing equations or representing entities of which substances are composed. Two types of data-collection techniques were used: (1) quantitative (administration of a six-item instrument in a pre-test??post-test design) and (2) qualitative (implementation of individual interviews with students). The target population for this investigation consisted of high-school students (N = 149) from several schools in Macedonia. The study was aimed to evaluate the effectiveness of an intervention program including deepened explanations, models, experiments, discussions and web animations on the cognitive achievement of students. The overall scores of the students were significantly higher in the post-test, thus pointing out the efficiency of the intervention program and the benefits gained during instruction. One-way ANOVA analysis showed that the four sub-samples (representing the four levels of study) were statistically different from one another both in the pre-test and in the post-test. In addition, the post hoc testing revealed that not all mean differences among pairs of sub-samples were statistically significant. Further on, t tests were used to inspect the effect of gender and interviews on students?? achievement. More than 15 misconceptions were registered both by test and interview analysis. Several of them, which could be characterized as deep-rooted misconceptions, remained (almost) unchanged after implementing the intervention program.

Keywords: high-school chemistry education, misconceptions, chemistry teaching, chemical reactions, symbolic representations, interviews

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Khimiya. 21, 853- (2012) Author(s): I. Burovska. S. Tsakovski:

Abstract.Students?? performances in ???Man & Nature??? (Fifth Grade), in part related to substances and their transformations, are analyzed. The main objective of the paper is to determine the extent to which students performances meet agreed deliverables in the curriculum. The study was conducted with 994 students from Fifth grade in Lovech, Bulgaria.

Keywords: chemistry education, educational standards, achievement test, assessment

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Khimiya. 21, 865- (2012) Author(s): M. Nur-E-Alam Siddiquee, H. Ikeda:

Abstract.The present study aims to explore the science teachers?? views on nature of science (NOS) in secondary schools of Bangladesh. By using Views of Nature of Science form-B (VNOS-B) questionnaire survey and follow up interviews, qualitative data was collected from purposively selected forty five science teachers. The VNOS-B data collection instrument is a six item, open ended questionnaire designed to elicit descriptive responses to generally agreed NOS aspects: tentative, empirical, inferential, creative, and subjective NOS, as well as the functions of, and relationships between theories and laws. Responses were analyzed into coded categories of informed, uninformed /na??ve, and ambiguous. The results of the study revealed a picture of the secondary science teachers?? views as well as misconceptions on nature of science. Their views on nature of science are mostly traditional (na??ve) and incoherent. The results of the study indicated that science teachers held traditional views regarding inference and theoretical entities, distinction and relationship between theories and laws, empirical, creative and imaginative nature of scientific knowledge. On the other hand, the participants have contemporary views (informed) on tentative and subjective nature of scientific knowledge. Analysis of interviews also supported these findings. Therefore, this study suggests further investigating on how the pedagogies of teacher education represent the NOS and what aspects of the NOS are communicated to the teachers through these pedagogies to find deeper understanding about the NOS.

Keywords: nature of science, teachers?? view, science teaching, secondary school,Bangladesh

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Khimiya. 21, 888- (2012) Author(s): B. Adinew:

Abstract.The review intended to describe the phytochemistry of turmeric (curcumin longa). Turmeric contains a wide variety of phytochemicals, including curcumin demethoxycurcumin, bisdemethoxycurcumin, zingiberene, curcumenol, curcumol, eugenol, tetrahydrocurcumin, triethylcurcumin, turmerin, turmerones, and turmeronols. Among these, the most active component of turmeric is curcumin which gives a yellow color to turmeric and responsible for most of the therapeutic effects. The physico-chemical properties of curcumin are dependent on the pH of the medium. This review helps of chemists to understand the phytochemistry of curcumin and its medicinal values in a better way.

Keywords: curcumin, phytochemistry, turmeric, curcuminoids

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Khimiya. 21, 898- (2012) Author(s): V. Simeonov:

Abstract.The serious problems of the environmental pollution require assessment not only of the absolute values of the controlled chemical pollutants but careful consideration of the potential toxicity. The major goal of the paper is to present some basic idea of the development of the ecological toxicology, to stress on the relationship between toxicity and dose of acceptance and to inform on the substantial chemical pollutants with respect to their toxic effects.

Keywords: toxicity, pollutants, xenobiotics, epidemiology

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Khimiya. 21, 920- (2012) Author(s): A. Milchev:

Abstract.The article is dedicated to academician Alexey Scheludko, the founder of Bulgarian school in the field of colloid chemistry, disperse systems and thin liquid films. Its basic purposes are, first, to inform the reader on the contributions of this eminent Bulgarian scientist to the field of electrochemical phase formation and crystal growth phenomena, and second to show how the pioneering works of Alexey Scheludko and his co-authors affected the subsequent, performed in Bulgaria, theoretical and experimental studies of electrocrystallization ?? a scientific field in which the contributions of Bulgarian physical chemistry school were universally recognized.

Keywords: colloid chemistry, disperse systems, thin liquid film, electrochemical nucleation, crystal growth, electrocrystallization

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