Alipaşa Ayas

Conceptual change achieved through a new teaching program on acids and bases

The purpose of this study was to investigate the effects on students‘ achievement and misconceptions of new teaching material developed for the unit ‘acids and bases”. Also, the students‘ attitudes towards chemistry were explored. The new material included worksheets based on the conceptual conflict strategy. The sample consisted of eighty-eight students. The research was carried out with an experimental/control group design, and lasted for four weeks. Two instruments ‘The Concept Achievement Test” and ‘Chemistry Attitude Scale” were used to collect data before and after the study as pre-tests and post-tests. The results from the post-tests indicated that the students in the experimental group, taught with the new teaching material, showed significantly greater achievement in the unit than did the students in the control group. In addition, the experimental group had a significantly higher score than the control group with regard to their attitudes toward chemistry. This shows that the implementation of the new material produced better results both in terms of achievement and attitudes. The students‘ misconceptions in experimental group were less than the control group. [Chem. Educ. Res. Pract., 2005, 6 (1), 36-51]

Evaporation in different liquids: secondary students’ conceptions

This study explores secondary school students’ understanding of evaporation and investigates whether students associate the concept of evaporation with only water as a liquid. An open‐ended written test was developed using three different words (water, liquid or alcohol) to state the question phrases. The test was implemented on a sample of 313 students at different levels of schooling. Clinical interviews, in which ethyl alcohol was used as an example of liquids, were also undertaken with 12 students, either individually or as a group. From the collected data, it was found that most of the students at different levels lack understanding of the concept and have several misconceptions. Various misconceptions of the evaporation concept that differ from those cited in the related literature were determined. The most important result was that students’ written responses showed some specific misconceptions when they were presented with the questions using three different words; liquid, water and alcohol.

A review of chemical bonding studies: needs, aims, methods of exploring students’ conceptions, general knowledge claims and students’ alternative conceptions

The present paper presents a detailed thematic review of chemical bonding studies. To achieve this, a matrix is developed to summarize and present the findings by focusing on insights derived from the related studies. The matrix incorporates the following themes: needs, aims, methods of exploring students’ conceptions, general knowledge claims, students’ alternative conceptions, implications and recommendations for teaching and learning, implications for curriculum development and suggestions for future research. The general knowledge claims investigated in this paper are: (a) student alternative conceptions and level of education; (b) studies of student understanding of covalent bonding; (c) studies of student understanding of ionic bonding; (d) studies of student understanding of metallic bonding; (e) studies of student understanding of intermolecular forces; (f) studies of student understanding of chemical bonds, energetics and other underlying theories; (g) student use of anthropomorphic language and analogies; (h) students’ mental models for chemical bonding; and (i) enhancing students’ conceptual understanding.

Promoting conceptual change in first year students’ understanding of evaporation

We constructed the PDEODE (Predict-Discuss-Explain-Observe-Discuss-Explain) teaching strategy, a variant of the classical POE (Predict-Observe-Explain) activity, to promote conceptual change, and investigated its effectiveness on student understanding of the evaporation concept. The sample consisted of 52 first year students in a primary science education department. The students’ ideas were revealed by a test consisting of eight questions. The PDEODE teaching strategy was designed on the basis of the students’ preconceptions. Conceptual change in students’ understanding of evaporation was evaluated by administering the same test as pre-, post and delayed post-test. The test scores were analyzed by both qualitative and quantitative methods. Statistical analysis using general linear model repeated measures of student test scores point to statistically significant differences in pre-, post-, delayed post tests and total scores (p<0.05), suggesting that the strategy helped students to achieve a better conceptual understanding. Further, no statistically significant differences were observed between post-test and delayed post-test scores, suggesting that teaching strategy enabled students to retain their new conceptions in their long-term memory.

Hydrogen resources : Conversion of black liquor to hydrogen rich gaseous products

Two precipitates were obtained from original black liquor by using hydrochloric acid and carbon dioxide. The precipitates were liqufied and gasificated by non-catalytic and catalytic runs at gradually elevated temperatures. The amount of gaseous products increased with increasing temperature and percent of catalyst. The percent of hydrogen in the obtained gas mixture was the highest in potassium carbonate catalytic runs (37 %).

Analogical Reasoning for Understanding Solution Rates: Students' Conceptual Change and Chemical Explanations.

The study aims to demonstrate evidence of (a) students’ conceptual change on solution rates; (b) students’ sub‐microscopic explanations of dissolution; and (c) retention of the concepts of solution rates. The sample consists of 44 Grade 9 students (18 boys and 26 girls) drawn purposively from two different classes (22 each) in the city of Trabzon, Turkey. The current study incorporates multiple methods of data collection: items from a solution concept test, clinical interviews and examination of students’ self‐assessment tasks. The results reveal that there is a statistically significant difference between scores in pre‐test and post‐test and between pre‐test and delayed test (p < 0.05). This research indicates that the intervention has improved students’ understanding of the conceptual relationship between solution rates and the sub‐microscopic explanation of dissolution. It has also helped in overcoming students’ alternative conceptions to some extent. However, alternative conceptions have not been eliminated completely. In the light of the results, this current study suggests that a simple model such as the four‐step constructivist teaching (4E) is efficient.

Utilization of lignite ash in concrete mixture

Abstract In this article 11 ashes from various Turkish lignite sources were studied to show the effects upon lignite ash quality for use as a mineral admixture in concrete. The lignite ashes were classified into two general types (Class A and Class B) based on total of silica, alumina, and iron oxide. Total content of the three major oxides must be more than 50 % for Class A lignite ash and more than 70 % for Class B lignite ash. When 25 % of the cement was replaced by LA-1 (Class A) lignite ash, based on 300 kg/m3 cementitious material, the 28-day compressive strength increased 24.3 % compared to the control mix. The optimal lignite ash replacement was 25 % at 300 kg/m3 cementitious material.

SUPERCRITICAL AND CATALYTIC FLUID EXTRACTIONS OF TEA WASTES

Abstract Air dried and ground tea waste was subjected to supercritical and catalytic fluid extraction by using water or acetone as solvent at different temperatures. The most important reactions variables were temperature and ratio of catalyst to the solid sample. The yields of the catalytic fluid reaction have been increased from 70.3 % to 92.4 % as the temperature increased from 230 °C to 340 °C by using water as solvent. The yield of extract was obtained from non catalytic supercritical water extraction was about 50.0 % at380°C.

Fen Bilgisi Ögretmen Adaylarının Kimya Konularında Sahip Oldukları Alternatif Kavramlar

The aim of this study is to determine alternative conceptions of prospective science teachers about the concepts of “Evaporation and Boiling”, “Acid-Base Neutralization Reactions”, “Dissolution and Factors Affecting Solubility”, “Gas Laws”, “Factors Affecting Reaction Rate” and “Electrochemical Cells”. The sample of the study conducted according to a case study consisted of 97 third-year students enrolled in Department of Science Teaching Programme in Faculty of Education in Giresun University. As the data collection tool, twotier Chemistry Concept Tests (CCTs) developed by Karslı (2011) was used in this study. The results obtained from CCTs’ data indicated that the prospective science teachers have various alternative conceptions about the chemistry concepts also reported in the literature and not mentioned in the literature. Within this research, possible causes of the alternative concepts determined in this study discussed, and some recommendations are presented for the elimination of these alternative concepts.

Voicing Mathematics Teachers: A Holistic Overview of Their Early Career Challenges

Citation: Keskin, Ö., Çorlu, M. S., & Ayas, A. (2018). Voicing mathematics teachers: A holistic overview of their early career challenges. Educational Sciences: Theory & Practice, 16, 331–371. http://dx.doi.org/10.12738/estp.2018.2.0025 1 Correspondence to: Özge Keskin, Graduate School of Education, Bilkent University, Ankara 06800 Turkey. Email: kabakci.ozge@gmail.com 2 BAUSTEM, Bahçeşehir University, İstanbul 34353 Turkey. Email: sencercorlu@gmail.com 3 Graduate School of Education, Bilkent University, Ankara 06800 Turkey. Email: apayas@bilkent.edu.tr Abstract Teachers’ further success in and commitment to their profession are shaped by their experiences in the early years of their careers. Being aware of the challenges that novices face would be helpful for teacher-educators in a way that would support pre-service teachers thoroughly. The goal of the current research is to ascertain the perceptions of secondary-school mathematics teachers about the challenging experiences at the beginning of their careers. With this purpose, semi-structured interviews were conducted. Findings revealed several issues that teachers face in four dimensions: mathematical knowledge for teaching, classroom management and organization, assessment of students’ learning, and the context of teaching. Also, teachers’ prior beliefs and expectations showed a general lack of awareness, oversimplified beliefs, and unrealistic optimism about the teaching profession. The findings of this study have shown a deficiency in teacher-education programs in terms of not providing pre-service teachers with enough knowledge of the challenges they may encounter, naturally resulting in the inability to reflect on the various reasons for those challenges and how all four aspects of teaching interact with one another. Regarding the findings, teacher education policies should be refined to help pre-service teachers to develop a more realistic and holistic view of teaching mathematics.