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    Effects of Deformation on Microstructure of Cu-Zn-Ni Alloy
    (Gazi Univ, 2012) Celik, Harun; Aldirmaz, Emine; Aksoy, Ilhan
    The thermal and mechanical effects on microstructure of Cu-12.44%Zn-4.75%Ni (wt%) alloy were investigated. The effects mechanical on both rapidly cooled sample and slowly cooled sample obtained from Cu-Zn-Ni alloy were investigated by using scanning electron microscopy (SEM), X-ray diffraction techniques (XRD). The thermal energy changes of in the alloy were examined by means of differential scanning calorimetry (DSC). As a result of SEM observations, annealing twins structures are observed in rapidly and slowly cooled samples. According to pictures of the SEM and XRD, the stress applied to samples caused to lose existing annealing twins, and led to formation of slip planes lying parallel to each other in between plates. The stress-strain behaviour is associated with applied heat treatment effect to samples. It's shown that the intensities of XRD peaks to be decrease, as a result of the increase in cooling rate. This result indicates that density defects of crystal increases with rapidly cooled in the Cu-Zn-Ni alloy. In both samples of the thermal energy changes, at the process of diffusion transformation eutectoid separation reactions have been proved to exist.
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    Effects of STEM-focused Arduino practical activities on problem-solving and entrepreneurship skills
    (Australasian Soc Computers Learning Tertiary Education-Ascilite, 2022) Sari, Ugur; Celik, Harun; Pektas, Huseyin Mirac; Yalcin, Selinay
    In this study, the effects of science, technology, engineering and mathematics (STEM) focused Arduino practical activities on problem-solving and entrepreneurship skills were analysed using qualitative and quantitative methods. Also, the contribution of these activities to teacher candidates and their effects on the learning-teaching process were discussed by evaluating their views. The study group consisted of 31 final-year teacher candidates studying in the science teaching department of a university in Turkey. The quantitative findings reveal that STEM-focused Arduino practical activities have a positive effect on improving the problem-solving and entrepreneurship skills of teacher candidates. Their opinions also support these results. The teacher candidates stated that the practical activities contribute to their professional development, support the development of 21st-century skills such as problem-solving and creativity and positively affect the learning-teaching process. As a result, STEM-focused Arduino practical activities are of significance in terms of adopting an interdisciplinary approach to education following the requirements of the century and developing problem-solving, entrepreneurial and productive individuals. Implications for practice or policy: STEM educators should integrate Arduino into STEM education to increase STEM learning outcomes. STEM educators should attach importance to STEM-focused Arduino activities to develop students' reflective thinking and entrepreneurial skills. Educators and researchers who want to use coding in STEM education may need to consider this article for example activities and implementation steps.
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    An Examination of Cross Sectional Change in Student's Metaphorical Perceptions towards Heat, Temperature and Energy Concepts
    (Necmettin Erbakan Univ, 2016) Celik, Harun
    In science teaching, metaphors are important tools for understanding meaningful learning and conceptual formation by the help of daily life language. This study aims to evaluate how the concepts of heat, temperature and energy are perceived by students in secondary school science classes and how the perceptions of these concepts vary in terms of metaphors depending on grade level ( 5th, 6th, 7th and 8th grades). The study group of the present research consists of 226 students selected from 5th, 6th, 7th and 8th graders through criterion sampling method. The descriptive method was used in the study and the data was collected by metaphor questionnaire. According to the findings, 176 metaphors were generated by students under four categories "formal/scientific metaphors", "Abstract metaphors", "Environmental/daily metaphors" and "misconception metaphors". When the findings were examined, it was seen that though there were some misconception detected about the concepts of heat, temperature and energy, conceptual changes in the other three categories vary depending on grade level. This variety needs to be discussed in relation to cognitive development and daily life. Some suggestions were made about the place and importance of metaphors in concept teaching for researchers and practitioners.
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    Teacher candidates' proficiency in utilising the REACT strategy through experimental activities
    (Inderscience Enterprises Ltd, 2023) Celik, Harun; Pektas, Huseyin Mirac; Karasahin, Abdulsamet; Karamustafaoglu, Orhan
    It is known that the success of a science education reform depends considerably on science teachers' knowledge, skills and activities. In accordance with this, the aim of this study is to investigate the proficiency of science teacher candidates in the use of the REACT strategy through their experimental science activities within the scope of context-based learning approach. Within this context, this study was designed in the form of a longitudinal analysis, performances were analysed periodically, and the transformation was pursued. The data obtained from documents by means of a content analysis was presented via graphical instruments through converting it into quantitative data by means of the rubric which was developed by the researchers. According to the longitudinal analysis findings, it was observed that the teacher candidates' performance in utilising the REACT strategy is parallel to the ascending number of activities.