Сп. „Химия“, книжка 2/2013

Education: Theory & Practice

Environmental Education in Bulgaria: International Background and Key Trends

Резюме. Content analysis of international and national documents on the state of the environment and environmental education reveals the human efforts to achieve sustainable development through competent management of the relationship with the environment. The paper presents topic developments of the Environmental Education, EE as reflected by the newsletter Connect, the interrelationship between global environmental issues and world possible solution measures. A conceptualization of Sustainable Development, SD and Environmental Sustainable Development, ESD is proposed. Some objective needs for further development of EE are discussed. Students’ evaluation of nature’s effects on their personal development is surveyed and the results are presented. Historical trends of EE as reflected in the four world conferences are outlined and on its background the main aspects of EE in Bulgaria are summarized. Conclusions on further trends in EE development are briefly pointed out.
Keywords: global environmental problems, international & national trends

Z. Kostova

New Approaches

Reversibility and Definition of Work

Резюме. The article points out a fundamental discrepancy between the definition of work from elementary mechanics, and how the expression for work is developed in most of the courses in chemical thermodynamics. A method of correcting this is suggested. This discrepancy is used as a heuristic tool to develop an easy to understand explanation of what the difference is between reversible and irreversible expansion of a gas, as well as transfer of heat. The explanation leads to a definition of reversible processes.
Keywords: thermodynamics, work, reversibility/irreversibility

J. Ahmad

Experiments

Techniques of the School Experiment in Sciences, for Bulgarian Students with Special Needs

Резюме. This study discusses the influence of teaching experiment in the mainstream schools and special schools in Bulgaria. The study presents teaching experiment related to the school subject Man &Nature. This school subject is part of the curriculum both at special and at mainstream schools. There are detailed explanations and descriptions as well as concrete methodological directions for each experiment. Some photographs are included in the text. In order to achieve better visualization of the experiments described. The developed experiments in Natural Sciences, for student with special needs, are just a small step in the understanding of the idea that all learners, regardless of their impairments, can participate in the learning process. This is in accord with the initiative of most nations to place more emphasis on the education of people with special needs, supporting their explorative aspirations and desideration to know the surrounding world.
Keywords: teaching experiment, Man & Nature, special needs

M. Zamfirov, S. Saeva

Experiments

Extraction-Spectrophotometry of Ion-Association Complexes [In Bulgarian]

Резюме. Ion-association complexes (IAC) are the basis of various analytical techniques, among which extraction-spectrophotometric are notable by virtue of their simplicity, low-cost instrumentation, high sensitivity and applicability for speciation analysis. In order to take maximum advantage of the great analytical potential of these compounds, the experimenter must be well acquainted with the theory of extraction-spectrophotometry and special features of the phenomenon of ion-association. The present paper discusses the most important practical and theoretical problems, concerning the chemical equilibrium of formation and liquid-liquid extraction of IAC. It is an attempt for a review and systematization of information, aiming at filling an existing literature gap.
Keywords: ion-associates, complex compounds, liquid-liquid extraction, equilibrium constants, spectrophotometry, review

K. B. Gavazov

Problems

Balancing Redox Reactions on Depending Two Degrees of Freedom: Investigation of the Domains for Selection of the Independent Parameters [In Bulgarian]

Резюме. The possibilities for balancing redox reactions depending on two degrees of freedom have been investigated. Similar reactions can be balanced with unlimited sets of non integer stoichiometric coefficients. The pairs of coefficients that can be independent parameters as well as the domains in which their values can be changed in order to obtained positive stoichiometric coefficients were determined.
Keywords: material balance method, redox reactions, two degrees of freedom, independent parameters

S. Petkova, M. Atanassova, A. Zahariev

Foreign Educational Tradition

Learning Environment of University Chemistry Classrooms in Iran

Резюме. In order to study the learning environment of university chemistry classrooms in Iran, Constructivist Learning Environment Survey (CLES) was carefully translated into Persian and administered to 415 (Male =204 and Female=211) Iranian university students. Data analyses attested to the sound factorial validity and internal consistency reliability of the Persian version of CLES. Comparison of Iranian university students’ scores on actual and preferred forms of the questionnaire revealed that students were not satisfied and preferred a more positive chemistry classroom environment on all scales. Favoring a constructivist perspective, this study proposes some measures that could be taken to improve university chemistry classrooms environments. The results will be of significance for chemistry educators to create more constructivist, creative, critical and democratic chemistry classrooms environments. The work is distinctive since it is the first learning environment study delving through chemistry classrooms in Iran.
Keywords: learning environments research, Constructivist Learning Environment Survey (CLES), Iranian chemistry classrooms, satisfaction

Z. Eskandari, NabiA. Ebrahimi

Advanced Science

Again About the End of the Periodic Table of Chemical Elements [In Bulgarian]

Резюме. It is a narrative about nuclear syntheses of flerovium and livermorium – presently, the heaviest elements of the Periodic table of the elements. The experiments for determination of chemical properties of flerovium and livermorium are described. On the basis of the available information, the problem of the upper limit of the Periodic table of chemical elements is also presented.
Keywords: flerovium, livermorium, periodic table

I. Kuleff

Personalities in Science

Hristo Kostov: The Course of Life and Scientific Activity [In Bulgarian]

Резюме. Hristo Kostov (1932-1982), assistant professor at the University of Sofia, was a specialist in didactics of physics. He was known as one of the most successful physics teachers in Bulgaria. The building of the astronomical observatory in Belogradchik was his idea.
Keywords: Hristo Kostov, teaching experiments in physics, Belogradchik high school, astronomical observatory

H. D. Dimitrov

Свързани статии:

Сп. „Химия“, книжка 1/2013 Сп. „Химия“, книжка 3/2013 Сп. „Химия“, книжка 4/2013 Сп. „Химия“, книжка 5/2013