Database of Publications

EXPLORING THE PHENOMENON OF “CHANGE OF PHASE” OF PURE SUBSTANCES USING THE MICROCOMPUTER-BASED-LABORATORY (MBL) SYSTEM

Evgenia Pierri, Anthi Karatrantou and Chris Panagiotakopoulos

RSC Publishing

2008

English

Research

Researchers, Teachers, Policy Makers

3 – 10 pages

The main aim of this research paper is to explore the possibility of helping Greek 1st grade Upper Secondary School students (15-16 y) to conceptualize the relation between the characteristics of pure substances (namely five saturated fatty acids of different molecular weight) and their melting - freezing point during the ‘change of phase’ phenomenon, by using the Microcomputer-Based Laboratory (MBL) system.

In the “Introduction” section the authors provide a concise literature review on students’ misconceptions and difficulties related with the concepts/phenomena of temperature, heat, internal energy, ‘change of phase’, latent heat of melting. In addition they provide a literature review on the ability of a laboratory teaching approach which makes parallel use of computer technology (MBL) to increase students’ motivation and “improve students’ perceptions of science concepts and cognitive skills such as observation and prediction”.

In the “Methodology” section the authors give detailed information about the student sample, the experimental procedure and the data collection and analysis procedure. The most important points are the following: There was a random selection of 79 students almost exactly distributed between the two genders. The students were prompted to work in groups by using a specific worksheet in order to exchange ideas and reach conclusions while working. Students performed the actual experiment and at the same time observed the graphics registering the real-time temperature changes on the computer screen. The data related to students’ perceptions and evaluation of the teaching procedure were collected by using three methods: videotape recordings, field notes and semi-structured interviews before, during and after the experimental procedure. The extracted students’ conceptions from the data analysis were categorized by type. Finally, it is noted that “when the research took place, students had already been taught the phenomenon ‘change of phase’ and the connection between the molecular weight of a pure substance and the melting – freezing point”.

In the “Results” section of the publication, the authors present the classification of the student conceptions regarding the chemical concept under study into four different types. Subsequently, they report the results regarding the students’ correct responses into seven different questions before and after the application of the experimental procedure. Results showed a statistically significant difference (p<0.01) in all seven questions. More specifically, “after the experiment more students responded correctly to all questions concerning the freezing point of the saturated fatty acids, the relationship of the freezing point to the molecular weight and the description of this relationship”. In addition, “there was no statistically significant difference concerning students’ responses and gender”. The authors present representative pieces of the recorded dialogues between the researcher and the students and make an effort to group students’ responses before and after the teaching intervention. The analysis of the responses which were related to the evaluation of the procedure gave insights into the reasons why the students seemed to prefer the performance of the experiment with the aid of the MBL system. In respect with the motivational aspects, it is stated characteristically that “they also admitted they were highly motivated by using sensors and computers and only one student reported that this type of experiment could not help him more than the traditional ones”.

In the “Conclusions” section, the authors brielfy summarize their findings regarding the effectiveness of the MBL system in improving students’ understanding of the phenomenon “change of phase” of pure substances and increasing their motivation to engage in the learning process.

This publication was chosen because it aims at assessing the effectiveness of a specific teaching intervention (namely the performance of a chemistry experiment with parallel use of computer technology – MBL system) in improving students’ understanding of a chemical phenomenon and motivation to learn. The authors base their research inspiration (understanding of phase change of a pure substance) on previously published research findings and they give quite detailed information on the experimental design. The paper uses clear language and the authors are careful in their choice of words in order to avoid data over-interpretation. In this way, the performed statistical analysis of the data provides evidence for the ability of the MBL system (chemistry laboratory assisted by computers for faster and more accurate data collection and graph production) to improve students’ understanding of the influence of molecular weight of saturated fatty acids on their freezing point. In addition, the authors provide some evidence for the increase in student motivation to engage in chemistry learning, even though they do not present detailed analysis of the relevant data. It would be interesting and useful if the authors explored in depth the relative effectiveness of the traditional chemistry laboratory and the computer-assisted chemistry laboratory (MBL system). This would strengthen significantly the results reached in this publication. Despite that, this remains a piece of work which provides us with an example of a successful teaching approach by justifying the “success” via the conduct of educational research.

T.E.I. of Ionian Islands