Exploring the phenomenon of ‘change of phase’ of pure substances using the Microcomputer-Based-Laboratory (MBL) system
نویسندگان
چکیده
We examined how 1 year students (10th grade) of Greek Senior High School could conceptualize the influence of the molecular weight of saturated fatty acids on the melting and the freezing point, during the ‘change of phase’ phenomenon using the Microcomputer-Based Laboratory (MBL) system. Students had to freeze a melted substance, observing at the same time the change of its temperature and trying to explain the temperature vs time curve. They used different saturated fatty acids in order to understand how the molecular weight of each organic acid affects the melting freezing point. Data about the students’ conceptualizations was collected using three methods: videotape recordings, field notes and supplementary semi-structured interviews. The analysis of the students’ responses to the same questions before and after the experiments showed statistically significant differences on their responses in every case. After the experiments there was a clear increase of correct responses concerning the freezing point of the saturated fatty acids, the relation of the freezing point to the molecular weight and the description of this relation.
منابع مشابه
A Microcomputer-Based Simulator for Digital Control Systems
A microcomputer-based simulator for digital control systems is proposed. The proposed simulator is a hybrid system in which the plant is simulated by conventional method of analog computers and other parts of the system including generation of input signal is performed digitally, using a Z-80 based microcomputer. To overcome the difficulty of programming in assembly language, and at the same ti...
متن کاملImproving Hydrophilicity of Polyethersulfone Membrane Using Silver Nanoparticles for Humic Substances Removal
Silver-impregnated membrane was facilely prepared by ex situ silver nanoparticles (NPs) blending method using polyethersulfone (PES) as the base polymer. A total of three membranes [F1(S0), F2(S0.5) and F3(S2.0)] were fabricated at different weight percentages of polymer and silver (Ag) loadings to compare their effects on membrane morphological and performance properties. All membrane types we...
متن کاملReal-Time Data Display, Spatial Visualization Ability, and Learning Force and Motion Concepts
In this study, we examined how students’ levels of spatial visualization ability interact with learning physics in a microcomputer-based laboratory (MBL) environment. Undergraduate students who had taken an introductory physics course based on MBL tools were preand posttested at the beginning and at the end of the semester on spatial visualization ability and their conceptual understanding of m...
متن کاملEffect of Temperature Changes on Dynamic Pull-in Phenomenon in a Functionally Graded Capacitive Micro-beam
In this paper, dynamic behavior of a functionally graded cantilever micro-beam and its pull-in instability, subjected to simultaneous effects of a thermal moment and nonlinear electrostatic pressure, has been studied. It has been assumed that the top surface is made of pure metal and the bottom surface from a metal–ceramic mixture. The ceramic constituent percent of the bottom surface ranges fr...
متن کاملAn Algorithm based on Predicting the Interface in Phase Change Materials
Phase change materials are substances that absorb and release thermal energy during the process of melting and freezing. This characteristic makes phase change material (PCM) a favourite choice to integrate it in buildings. Stephan problem including melting and solidification in PMC materials is an practical problem in many engineering processes. The position of the moving boundary, its veloci...
متن کامل