Hüseyin Kalkan

Science and Nonscience Students' Ideas about Basic Astronomy Concepts in Preservice Training for Elementary School Teachers.

A 14-item questionnaire was given to 100 students in preservice training to become primary and secondary education faculty. Results showed that science and non-science majors held a series of misconceptions about several basic topics central to astronomy. The changes in astronomy misconceptions were analyzed by means of a written questionnaire completed by the students at the beginning of the semester and again at the end. Results were interpreted through comparison with the literature. In this study, some misconceptions were easy to change, even with limited instructional effort, and some were very difficult to change despite rigorous, focused instruction on basic astronomy and the universe. Results and the reasons are discussed according to the gain index, the actual percentage gain over the possible percentage gain.

(Z)-6-[(2-Fluorophenyliminio)methyl­ene]-2,3-dihydroxy­phenolate

The title compound, C13H10FNO3, crystallizes in a zwitterionic form. The dihedral angle between the aromatic rings is 21.69 (9)°. O—H⋯O hydrogen bonds generate a centrosymmetric R22(10) dimer and the dimers are linked by O—H⋯O hydrogen bonds into sheets parallel to (10\overline{1}).

Teaching seasons with hands-on models: model transformation

Abstract The purpose of this study was to examine the effects of using ‘hands-on’ models (HOMs) to teach the subject of seasons – a topic about which students often have misconceptions – on students’ expressed models. To this end, three different HOMs were developed. The study sample consisted of 80 seventh graders (ages 12–13). The study had a quasi-experimental design, and a model with a control group was used. The experimental group and the control group were assigned randomly. The study data were collected using an open-ended question form that was administered three times: pre-instruction, post-instruction and a long time after instruction (permanence). The collected data were analysed using the content analysis technique. Frequencies and percentages were used to analyse the changes in the students’ expressed models. The results of the analyses showed that using HOMs was an effective method for teaching the subject of seasons. It was concluded that whereas teaching with HOMs led the students to a ‘scientific’ model, the teaching method used in the control group led the students to a ‘synthesis’ model. In addition, the learning that occurred in the group taught with the HOMs was found to be more permanent than the learning that occurred in the control group. Based on these results, the use of HOMs to teach astronomy and the generalisation of these models has been recommended. Lastly, issues to consider when teaching the subject of seasons have been outlined.

EPR OF UV PHOTOLYZED TETRAMETHYLAMMONIUM ACETATE AND TRIBUTYLTIN ACETATE POWDERS

The electron paramagnetic resonance investigation of tetramethylammonium acetate ((CH 3)4 NCH 3 COO) and of tributyltin acetate ((C 4 H 9)3 SnCH 3 COO) powders under UV photolysis were carried out at 120 K. Some damage centers were formed by the UV photolysis which are attributed to ĊH 3 and CO − 2 radicals in the first substance and to radical in the second. The g values of the radicals were found to be 2.0642, 2.0305 and 2.0058 respectively. No signals were detected at different doses of the gamma irradiation and UV photolysis for both samples at the room temperature.

EPR Study of the Dynamic Jahn-Teller Effect of Cu2+ in CdBa(HCOO)4 · 2H2O Single Crystals

Abstract Electron Paramagnetic Resonance spectra of Cu2+ doped into cadmium barium formate dihydrate single crystal were studied at 300 K. The powder spectrum of this material was studied at 300 to 133 K. The values of the g and A hyperfine tensors were found to be temperature dependent. The temperature dependence of the Cu2+ EPR spectrum is discussed in terms of the dynamic Jahn-Teller effect. The angular variation of the spectra indicates the substitution of the host Cd2+ with Cu2+ . The spectra were fitted with a tetragonal spin-Hamiltonian, the parameters of which were determined at 300 K. The ground-state wave function of the copper complex has been constructed at 113 K and 300 K.

EPR Study of the Dynamic Jahn-Teller Effect of Cu2+ in Cd(HCOO)22H2O Single Crystals

Abstract The X-band EPR spectra of Cu+ doped into cadmium formate dihydrate single crystal was studied at 113 °K. The powder spectrum of the same material was studied over the temperature range from 113 to 300 °K The observed values of the g and A hyperfine coupling constants and linewidths were found to be temperature dependent. The temperature dependence of Cu2+ EPR spectrum values were discussed in terms of dynamic Jahn-Teller effect. The tensor elements of g and A were calculated from the polycrystalline samples at various temperature and it is found that the spectrum at 113 °K has given fallowings, g xx=2.108±0.002, g yy=2.085±0.002, g zz=2.431±0.002 and A xx=48±1, A yy=17±1, A zz=11±1 Gauss.

EPR Studies of VO2+ in Ba(ClO4) 2 ・3H2O Single Crystals

The results of an electron paramagnetic resonance (EPR) study of vanadyl ion VO2+ doped in single crystals of Ba(ClO4)2 - 3 H2O are reported. The spectra indicated the presence of two substitutional and interstitial sites depending on the orientation. The spin-Hamiltonian parameters were determined from single crystal and powder EPR data. These parameters were found to be axial symmetric for the powder sample, whereas they showed deviations from axial symmetry for the single crystal