|A.I. Gambari, A.A. Yaki, T.T. Olowe|
Understanding the Concept of Digestive System in Biology Using Computer Simulation
Full text: PDF (1515 K)
|V. Tzvetkov, E. Boiadjieva|
Forming Key Competencies by Problem-Based Learning of Chemistry in Secondary School [In Bulgarian]
Full text: PDF (367 K)
|J.E. Hollenbeck, M. Kirova, E. Boiadjieva, A. Tafrova-Grigorova|
Snapshot of Science Classroom Teaching from the Point of View of Ideas of Constructivism: A Case Study - Secondary Schools in Sofia, Bulgaria
Full text: PDF (312 K)
Explanation of Facts and Phenomena in Chemistry Education - Constructivist Approach [In Bulgarian]
Full text: PDF (527 K)
|I. Hadjiali, T. Kolarova|
Application of Reflective Approach to the Biology Teaching in Secondary Schools (9th - 11th Grade)[In Bulgarian]
Full text: PDF (710 K)
Two Investigations of Examiners' Perceptions of Prior Knowledge Required for Solving Stoichiometric Problems and Its Relationship to Students' Prior Knowledge
Full text: PDF (424 K)
About the Chemistry of the Beer [In Bulgarian]
Full text: PDF (966 K)
|History and Philosophy of Science:|
Nobel Laureates in Chemistry from the Territory of Former Yugoslavia
Full text: PDF (950 K)
The Meteorite from Belogradchik [In Bulgarian]
Full text: PDF (698 K)
|New Information Media:|
|S. Zabunov, M. Gaydarova|
Binet Construction in Online Stereo 3D Visualization
Full text: PDF (857 K)
|B.V. Toshev (Ed.)|
Teaching Science in the Bulgarian Schools for Girls (1897): Natural History [In Bulgarian]
Full text: PDF (373 K)
Khimiya, Volume 22, Issue 5(2013)
Khimiya. 22, 649-661 (2013) Author(s): A.I. Gambari, A.A. Yaki, T.T. Olowe:
Abstract.This study examined understanding the concept of digestive system in biology using computer simulation. It also determined whether the performance of the students would vary with gender when exposed to computer simulation package (CSP) and biology instructional model (BIM). Participants were 60 senior secondary II (SSII) biology students drawn from three schools in Minna, Niger State, Nigeria. The schools were randomly assigned to experimental and control groups. The experimental group I was taught the concept of digestive system using CSP, experimental group II was exposed to BIM and conventional method was used for the control group. A 20-item Biology Achievement Test (BAT) was validated and its reliability determined as 0.78 using Kuder-Richardson (KR-21). The data collected were analyzed with t-test, ANOVA and Scheffe's post-hoc test. The results revealed that there was significant difference in the mean performance scores of students in experimental groups (I & II) and control group. There was no significant difference between the mean scores of male and female students taught biology using computer simulation package, implying that the package is gender friendly. Also, no significant difference was found between the mean scores of male and female students taught biology using biology instructional model. Based on the findings, it was concluded that the use of the computer simulation package was more effective than the biology instructional model and conventional method of teaching respectively. Therefore, it was recommended that use of computer simulation for teaching the concept of digestive system should be encouraged.
Keywords: computer simulation, biology, instructional model, digestive system, gender
Khimiya. 22, 662-675 (2013) Author(s): V. Tzvetkov, E. Boiadjieva:
Abstract.The modern society sets to young people a variety of requirements and challenges. They are expected to take the initiative, to react quickly in new and unknown situations, to collect new information. Therefore, a need for changing in educational policies and practices is expected. This article advocates for using a problem-based approach of teaching when key competencies are formed. The conducted research with 9th grade students shows a trend of positive attitude towards learning and successful formation of important key skills. The opinion of students on the applied method is measured with a CLES questionnaire.
Keywords: problem-based learning, key competencies, chemistry
Khimiya. 22, 676-681 (2013) Author(s): J.E. Hollenbeck, M. Kirova, E. Boiadjieva, A. Tafrova-Grigorova:
Abstract.This paper provides the argument for in-service teacher training for secondary science educators in Bulgaria. Teachers need content knowledge as well as updated teaching methodologies. Observations of Bulgarian science classrooms confirmed the results of previous studies: Bulgarian teachers blend teacher-centered and student-centered style of teaching methodology. Bulgarian classrooms will be more effective if teachers are reintroduced to the constructivist, inquiry, problem-solving teaching methodology. Teachers need in-service constructivist-based education sponsored by the education departments of chemistry, biology, physics and mathematics faculties.
Keywords: constructivist environment, ESTEEM, science classroom teaching
Khimiya. 22, 682-694 (2013) Author(s): Y. Stefanova:
Abstract.In our days the development of science education is based on the constructivist ideas. In these ideas most important for studying is the own experience of the students in their interaction with the environment. Considering the goals of chemistry education, the special features of chemistry knowledge, the necessity of education orientated to the students and the opportunities for change in the school, we introduce in the present article a didactical model for explaining the facts and phenomena in the light of basic ideas of constructivism. The model was carefully defined and approved by practice.
Keywords: scientific explanation, chemistry education, constructivism
Khimiya. 22, 695-723 (2013) Author(s): I. Hadjiali, T. Kolarova:
Abstract.The paper advocates for the application of reflective approach to the Biology teaching in the secondary schools (9th -11th grades). The main features of this approach are carefully described. The corresponding model of teaching is proposed. This model was successfully used in three secondary schools in Bulgaria. The results of this longitudinal study are presented and discussed.
Keywords: high school biology education, reflection, intellectual reflection, personal reflection, reflective approach, principles of reflective approach
Khimiya. 22, 724-745 (2013) Author(s): A.E. Okanlawon:
Abstract.The aim of this paper is to examine three interrelated research questions: (1) what prior knowledge do examiners perceive as required for solving a stoichiometric problem considered in this study; (2) which of the perceived prior knowledge are needed to be primed (activated) based on students’ performance in a diagnostic test; (3) which of the perceived prior knowledge are needed to be taught based on students’ performance in a diagnostic test. Research question (1) was examined firstly by a phenomenographic analysis of the transcripts of the examiners’ interview using coding categories. Seventeen participants were engaged in the first investigation. Their participation in this research was voluntary. Semi-structured interviews were employed as the main instrument for collecting statements about prior knowledge required for solving a sample stoichiometric problem. Prior knowledge needed for solving a stoichiometric problem considered in this study as perceived by the examiners was reported as a diagrammatic representation. Deciding instructionally on whether those perceived prior knowledge are to be activated or taught is based on students’ performance in a diagnostic test and this also prompted a follow-up study in which the author included research questions (2) and (3). In the second study, the subjects are 281 second year senior secondary school students in science classes obtained from five randomly selected schools. They were subjected to diagnostic testing using Stoichiometry Prior Knowledge Achievement Test (SPKAT) to determine the presence or absence of examiners’ perceived prior knowledge in students’ schema. The author qualitatively analyzed the content of students’ written solutions to obtain information about students’ capabilities using content analysis. Results of the second study indicate that many of the students demonstrated proficiency in the following skills: interpreting chemical equations, writing mole-mole factor, calculating partial pressure of a gas and calculating number of moles of a gas from given quantities of gas. So, these content areas are to be activated only. However, most students need to develop proficiency in areas identified as critical prerequisites such as balancing of redox equation, determination of molar concentration, and construction of appropriate mole-mole ratio and its further application in calculation. So, these content areas are to be taught. Results of both investigations are discussed in terms of chemistry instruction.
Keywords: Problem solving instruction, examiners’ perceptions, students’ prior knowledge, knowledge components, stoichiometry
Khimiya. 22, 746-755 (2013) Author(s): I. Kuleff:
Abstract.In the paper is presented the technology of the production of the beer today. The technology of beer is connected with transformation of different chemical substances in the starting products during the technological processes. The information about production of beer in the past as well as the methods of determination of the beer is also discussed.
Keywords: beer production, chemical reactions, fermentation, Bulgarian beer
Khimiya. 22, 756-763 (2013) Author(s): M.D. Stojkovic:
Abstract.Until the disintegration of the former Yugoslavia, SFRY (1991/92), for 74 years (from 1918) people of the region lived in a common country and a single common scientific and cultural-linguistic area (creating a unique school system, founding numerous school-educational institutions throughout the country, educating many generations of students in official Yugoslav languages). During the period between the two World Wars and after World War II Yugoslav chemists (of Yugoslav origin, born on the territory of the former Austro-Hungary), Fritz Pregl, Lavoslav Ruzicka (Ružička) and Vladimir Prelog, with their professional, scientific, practical (experimental) and cultural work, placed themselves (and the country where they were born, educated and gained their first knowledge) among distinguished world scientists, winners and holders of the prestigious international Nobel Prize. The aim of this scientific work is not only to present the lives and work of the abovementioned chemists, Nobel laureates, but also to overcome the existing cultural-political and scientific-educational differences among the former Yugoslav states that undoubtedly share common culture, language and science, which is proven and confirmed by the extensive work of these eminent scientists on the development of science and education in the former SFRY and the promotion of the common Yugoslav science in the world, who all „former“ Yugoslavs can rightly be proud of.
Keywords: Yugoslav scientists, Nobel laureates, chemistry
Khimiya. 22, 764-769 (2013) Author(s): B.V. Toshev:
Abstract.For the first time the Bulgarians have the opportunity to see how the meteorite of Belogradchik (Virba) looks like: the first picture is from the Hungarian Museum of Natural History in Budapest; the second picture is from Natural History Museum in London.
Keywords: meteorites, hondrites, Virba
Khimiya. 22, 770-777 (2013) Author(s): S. Zabunov, M. Gaydarova:
Abstract.The present paper describes an interactive online stereoscopic 3D visualization aimed at e-learning rigid body mechanics. The visualization is realized using a numerical simulation. This learning tool demonstrates free rigid body motion while visualizing the Binet construction. The visualization and the underlying simulation was developed with the idea to help students in their understanding of Newtonian mechanics, mastering its underlying mathematical apparatus and creating a method for observation of phenomena hard to realize in laboratory conditions, such as absence of gravity. The Binet construction is interactively presented in 3D graphics with all of its inherent elements, such as invariant ellipsoid, invariant sphere, angular momentum vector trajectory, etc. The simulation also demonstrates a large number of vector and scalar parameters. This material is directed to university students taking the Analytical (Mathematical) Mechanics courses and Theoretical Physics and General Physics courses. It may be used at any university – the simulation is published with free access on the Internet without restrictions of any kind (http://ialms.net/sim/).
Keywords: Binet construction, Poinsot construction, interactive simulation of free rigid body motion, mechanics in stereo 3D e-learning