COMPARING MALE AND FEMALE PRE-SERVICE TEACHERS‘ UNDERSTANDING OF THE PARTICULATE NATURE OF MATTER

2014 ◽  
Vol 13 (6) ◽  
pp. 821-827
Author(s):  
Frackson Mumba ◽  
Vivien Mweene Chabalengula ◽  
Asiana Banda
Keyword(s):  
Phase Change ◽  
Science Teachers ◽  
Teaching And Learning ◽  
Phase Changes ◽  
Particulate Nature Of Matter ◽  
Male And Female ◽  
Size Of Particles ◽  
Gender Groups ◽  
Key Words Gender ◽  
Number Of Particles

This study compared male and female pre-service science teachers’ understanding of the effect of phase changes and physical transformation of matter on the size of particles, spaces between particles, speed of particles, and number of particles. Data were collected using a questionnaire that has 36 items. Both gender groups had sound understanding of the effect of phase change on speed, spaces, and number of particles in a substance, and the effect of compression on speed, number, size and spaces between particles in solids and liquids. However, most female pre-service teachers had low understanding of the effect of phase change on the size of the particles in solids, liquids and gases as most of them incorrectly believed that heating increases the size of the particles and cooling decreases the size of particles. The results have implications for science teaching and learning and teacher education. Key words: gender, matter, particle, pre-service teachers, understanding.

Influence of Metal Substitution on the Pressure-Induced Phase Change in Flexible Zeolitic Imidazolate Frameworks

2018 ◽  
Author(s):  
C. Michael McGuirk ◽  
Tomče Runčevski ◽  
Julia Oktawiec ◽  
Ari Turkiewicz ◽  
mercedes K. taylor ◽  
...  
Keyword(s):  
Phase Change ◽  
Single Crystal ◽  
Gas Adsorption ◽  
High Capacity ◽  
Phase Changes ◽  
Zeolitic Imidazolate Frameworks ◽  
Metal Substitution ◽  
Heat Management ◽  
Metal Organic ◽  
First Time

<p>Metal–organic frameworks that display step-shaped adsorption profiles arising from discrete pressure-induced phase changes are promising materials for applications in both high-capacity gas storage and energy-efficient gas separations. The thorough investigation of such materials through chemical diversification, gas adsorption measurements, and <i>in situ </i>structural characterization is therefore crucial for broadening their utility. We examine a series of isoreticular, flexible zeolitic imidazolate frameworks (ZIFs) of the type M(bim)<sub>2</sub> (SOD; M = Zn<sup> </sup>(ZIF-7), Co (ZIF-9), Cd (CdIF-13); bim<sup>–</sup> = benzimidazolate), and elucidate the effects of metal substitution on the pressure-responsive phase changes and the resulting CO<sub>2</sub> and CH<sub>4</sub> step positions, pre-step uptakes, and step capacities. Using ZIF-7 as a benchmark, we reexamine the poorly understood structural transition responsible for its adsorption steps and, through high-pressure adsorption measurements, verify that it displays a step in its CH<sub>4 </sub>adsorption isotherms. The ZIF-9 material is shown to undergo an analogous phase change, yielding adsorption steps for CO<sub>2</sub> and CH<sub>4</sub> with similar profiles and capacities to ZIF-7, but with shifted threshold pressures. Further, the Cd<sup>2+</sup> analogue CdIF-13 is reported here for the first time, and shown to display adsorption behavior distinct from both ZIF-7 and ZIF-9, with negligible pre-step adsorption, a ~50% increase in CO<sub>2</sub> and CH<sub>4</sub> capacity, and dramatically higher threshold adsorption pressures. Remarkably, a single-crystal-to-single-crystal phase change to a pore-gated phase is also achieved with CdIF-13, providing insight into the phase change that yields step-shaped adsorption in these flexible ZIFs. Finally, we show that the endothermic phase change of these frameworks provides intrinsic heat management during gas adsorption. </p>

Science Teachers’ Beliefs about Teaching and Learning Implementing Inquiery-based Learning - A Case in Qatar Government Primary Schools

2020 ◽  
Author(s):  
Alshaima Saleh Alyafei
Keyword(s):  
Science Teachers ◽  
Primary Schools ◽  
Teaching And Learning ◽  
Traditional Approach ◽  
Teaching Experience ◽  
Web Based ◽  
Years Of Teaching Experience ◽  
Teachers Beliefs ◽  
Beliefs About Teaching ◽  
Voluntary Basis

The current study investigates the beliefs held by science teachers on constructivism and a traditional approach in Qatar government primary schools. More specifically, it aims to investigate the challenges that science teachers experience during inquiry-based learning implementation. A web-based survey was conducted in order to collect data from grades 4 to 6 science teachers. A total of 112 science teachers responded and completed the survey on a voluntary basis. The results indicate that science teachers hold a higher beliefs in constructivism than traditional approach. A T-test and ANOVA analysis have showed that there is no significant differences between the beliefs of science teachers’ and their gender, level of education, and years of teaching experience. In addition, science teachers faced challenges in lesson planning, assessment, and teacher support.

A Glance Portrayal of Science Education in Indonesia

2019 ◽  
Author(s):  
Adib Rifqi Setiawan
Keyword(s):  
Science Education ◽  
General Education ◽  
Science Teachers ◽  
Teaching And Learning ◽  
Science Teacher Education ◽  
Asia Pacific ◽  
Professional Organizations ◽  
Curriculum Innovation ◽  
Global Science ◽  
Historical Developments

The goal of this work is to describe pre- and in-service science teacher education and science education research in Indonesia in an effort to better inform the global science education community about historical developments and present challenges. We begin by providing an historical overview of the general education system to provide readers with context needed to understand current reform initiatives. Next we describe the current-day process for preparing and certifying science teachers and we describe some of the challenges facing teachers, students, and researchers in Indonesia’s science education context today. We follow this discussion with an introduction to some existing professional organizations for teachers and researchers in Indonesia that are working to develop important channels for disseminating current research on teacher practice, curriculum innovation, and student learning that have the potential to positively influence on teaching and learning in the future. We conclude by highlighting some areas that would benefit from additional research and by inviting more international collaborative research initiatives with colleagues in the Asia-Pacific region and beyond.

scholarly journals Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3634
Author(s):  
Grzegorz Czerwiński ◽  
Jerzy Wołoszyn
Keyword(s):  
Mass Transfer ◽  
Phase Change ◽  
Heat Dissipation ◽  
Cooling System ◽  
Numerical Study ◽  
Relaxation Parameter ◽  
Phase Changes ◽  
Transfer Time ◽  
Two Phase ◽  
Time Relaxation

With the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a modification of the evaporation–condensation model implemented in ANSYS Fluent. The modification was to manipulate the value of the mass transfer time relaxation parameter for evaporation and condensation. The developed model in the form of a UDF script allowed the introduction of additional source equations, and the obtained solution is compared with the results available in the literature. The variable value of the mass transfer time relaxation parameter during condensation rc depending on the density of the liquid and vapour phase was taken into account in the calculations. However, compared to previous numerical studies, more accurate modelling of the phase change phenomenon of the medium in the thermosyphon was possible by adopting a mass transfer time relaxation parameter during evaporation re = 1. The assumption of ten-fold higher values resulted in overestimated temperature values in all sections of the thermosyphon. Hence, the coefficient re should be selected individually depending on the case under study. A too large value may cause difficulties in obtaining the convergence of solutions, which, in the case of numerical grids with many elements (especially three-dimensional), significantly increases the computation time.

Phase changes and convection in the Earth’s mantle

1965 ◽  
Vol 258 (1088) ◽  
pp. 276-283 ◽  
Keyword(s):  
Temperature Gradient ◽  
Phase Change ◽  
Initial Temperature ◽  
Phase Changes ◽  
Homogeneous Layer ◽  
Transformation Zone ◽  
Earth’S Mantle ◽  
Transition Level ◽  
Transformation Rates

A phase change may hinder or enhance convection, depending on its characteristics. Univariant transformations such as may occur in the mantle constitute a barrier to convection unless the motion starts at some distance above or below the transition level; an initial temperature gradient in excess of the adiabatic value is also required. Multivariant transformations only require, in the transformation zone, an initial gradient slightly greater than the adiabatic value for a homogeneous layer. The effect on convection of transformation rates is not likely to be serious.

English Medium of Instruction in Multilingual Science Classes: Teaching Science or Language?

2021 ◽  
Vol 4 (1) ◽  
pp. 44-59
Author(s):  
Dor Prasad Bhandari
Keyword(s):  
Science Teachers ◽  
Teaching And Learning ◽  
Teaching Science ◽  
Kathmandu Valley ◽  
Medium Of Instruction ◽  
English Medium Of Instruction ◽  
Science Classes ◽  
Depth Interviews

English medium of instruction in multilingual science classes: teaching science or language? is an attempt to identify the effects, methods, and approaches of teaching science in English medium of instruction in Multilingual (ML) science classes. The article is prepared on the basis of in-depth interviews taken with science teachers who are teaching science in multilingual classes. Three science teachers are selected purposively from different three (English Medium Instructions) EMI schools of Kathmandu valley. After taking the interview it was transcribed, coded, and generated the theme. Based on the themes generated it was found that the EMI is important for teaching and learning but it is not everything. Similarly, it was found that the teaching of science is not similar to teaching the grammar structures, and always not possible to use English as a medium of making the concept clear of theoretical ideas of science.

BETTER LEARNING AND INCREASED MOTIVATION TO LEARN WITH MOBILE TECHNOLOGY (DEVICES): A PRELIMINARY STUDY

2019 ◽  
Vol 16 (2) ◽  
pp. 80-88
Author(s):  
Vincentas Lamanauskas ◽  
Violeta Slekiene ◽  
Gabriel Gorghiu ◽  
Costin Pribeanu
Keyword(s):  
Science Teachers ◽  
Mobile Technology ◽  
Teaching And Learning ◽  
Educational Process ◽  
Mobile Technologies ◽  
Motivation To Learn ◽  
Teachers And Students ◽  
Preliminary Study ◽  
Teaching Learning ◽  
Educational Potential

Mobile technology is now part of the everyday life of teachers and students and thus tends to become an inseparable part of the educational activities. Teachers and students are increasingly using mobile technologies in teaching and learning. Therefore, it is purposeful to responsibly integrate technologies into the educational process. However, technical and pedagogical support is necessary in order to facilitate both teacher and students’ understanding of this educational potential. Besides, it is still very little known and there is very little evidence about the effectiveness of the application of these technologies in the teaching/learning process. This research aims to explore the perceptions of Romanian and Lithuanian teachers regarding the use of mobile technologies in education. Keywords: motivation to learn, mobile technology, preliminary study, science education, science teachers.

Thermodynamic Nonequilibrium Phase Change Behavior and Thermal Properties of Biological Solutions for Cryobiology Applications

2004 ◽  
Vol 126 (2) ◽  
pp. 196-203 ◽  
Author(s):  
Bumsoo Han ◽  
John C. Bischof
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Latent Heat ◽  
Thermodynamic Equilibrium ◽  
Low Temperatures ◽  
Eutectic Phase ◽  
Phase Changes ◽  
Chemical Additives ◽  
Change Behavior ◽  
Saline Solutions

Understanding the phase change behavior of biomaterials during freezing/thawing including their thermal properties at low temperatures is essential to design and improve cryobiology applications such as cryopreservation and cryosurgery. However, knowledge of phase change behavior and thermal properties of various biomaterials is still incomplete, especially at cryogenic temperatures ⩽−40°C. Moreover, in these applications, chemicals are often added to improve their outcome, which can result in significant variation in the phase change behavior and thermal properties from those of the original biomaterials. These chemical additives include cryoprotective agents (CPAs), antifreeze protein (AFP), or cryosurgical adjuvants like sodium chloride (NaCl). In the present study, phase change behavior and thermal properties of saline solutions–either water-NaCl or phosphate buffered saline (PBS)–with various chemical additives were investigated. The chemical additives studied are glycerol and raffinose as CPAs, an AFP (Type III, molecular weight=6500), and NaCl as a cryosurgical adjuvant. The phase change behavior was investigated using a differential scanning calorimeter (DSC) and a cryomicroscope. The specific and latent heat of these solutions were also measured with the DSC. The saline solutions have two distinct phase changes–water/ice and eutectic phase changes. During freezing, eutectic solidification of both water-NaCl and PBS are significantly supercooled below their thermodynamic equilibrium eutectic temperatures. However, their melting temperatures are close to thermodynamic equilibrium during thawing. These eutectic phase changes disappear when even a small amount (0.1 M glycerol) of CPA was added, but they are still observed after the addition of an AFP. The specific heats of these solutions are close to that of ice at very low temperatures ⩽−100°C regardless of the additives, but they increase between −100°C and −30°C with the addition of CPAs. The amount of latent heat, which is evaluated with sample weight, generally decreases with the addition of the additives, but can be normalized to approximately 300 J/g based on the weight of water which participates in the phase change. This illustrates that thermal properties, especially latent heat, of a biomaterial should be evaluated based on the understanding of its phase change behavior. The results of the present study are discussed in the context of the implications for cryobiology applications.

scholarly journals Pre-service Science Teachers’ Integration of Constructivist Ideas in the Lecture Method

2021 ◽  
Vol 20 (6) ◽  
pp. 277-298
Author(s):  
Rose Atieno Mutende ◽  
Rosemary K Imonje ◽  
Winston Akala
Keyword(s):  
Instructional Practices ◽  
Science Teachers ◽  
Teaching And Learning ◽  
Teaching Practice ◽  
Sub Saharan Africa ◽  
Learning Material ◽  
Science Students ◽  
University Supervisors ◽  
Lecture Method ◽  
Sub Saharan

The teaching and learning of science subjects at secondary schools in Sub-Saharan Africa is currently dominated by application of the lecture method in delivering learning material. In the Lecture Method, the teacher discusses and shows the learning material. Studies showed that the lecture method can be made interactive, and, hence, more effective if teachers appropriately integrate constructivist ideas in the method. Therefore, this study aims to examine the BEd (Science) students’ integration of constructivist’s learner-oriented instructional practices in the lecture method during teaching practice (TP). Data were collected from 107 BEd(Science) students, their Head of Subjects in the TP schools and the university supervisors at the onset and towards the end of a 14-week TP. The instruments used to collect data were questionnaires and interview schedules. The data were analysed descriptively and inferentially. Descriptive statistics focused on frequencies, percentages, means and standard deviation which summarised the variables in terms of demonstration of instructional practices, supervision and assessment practices. Findings revealed that the BEd(Science) students faced difficulties in their attempt to integrate constructivist ideas in the lecture method. T-test showed a positive effect of teaching practice on the integration of constructivists’ ideas in the lecture method. The study provides several recommendations based on the findings.

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