Now showing 1 - 10 of 15
  • Publication
    Open Access
    Ions and ionisation energy
    (Curtin University, 2003) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
    ;
    Taber, Keith S.
    Previous research (Taber, 1999, 2000a) has shown that A-level students in the United Kingdom had difficulty understanding the concepts involved in ionisation energy. The purpose of this study, which involved the use of interviews and written instruments, was to determine if Grades 11 and 12 students (16 to 19 years old) in Singapore had similar alternative conceptions and explanatory principles of the factors influencing ionisation energy as their A-level counterparts in the United Kingdom (U.K.), as well as to explore students' conceptions of the trend of ionisation energy across different elements in the Periodic Table. The results showed that many students in Singapore applied the same octet rule framework and conservation of force thinking to explain the factors influencing ionisation energy as students in the U.K. In addition, the students resorted to relation-based reasoning to explain the trend of ionisation energy across period 3 elements. The authors believed that the way ionisation energy was taught.and presented in textbooks could be the cause of students' difficulties in understanding ionisation energy. Teachers and textbooks need to focus explicitly on the effects of nuclear charge, the distance of the electron from the nucleus, the repulsion/screening effect of the other electrons present, and the interplay between these factors to explain the factors influencing ionisation energy and the trend in ionisation energy across period 3.
      197  322
  • Publication
    Open Access
    Qualitative analysis practical work: An instructional package
    (The Association for Science Education, 2004-06) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
    ;
    Treagust, David F.
    Previous research has shown that grade 10 students in Singapore find quaiitative analysis practical work difficult to understand and carry out, and unrelated to the theory they had learned in class. This article describes a teaching package developed explicitly to teach the concepts, processes and thinking skills involved in qualitative analysis.
      429  1828
  • Publication
    Open Access
    Teaching and learning difficult chemistry topics: The need for a content framework
    (2000-09) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
    ;
    Treagust, David F.
    Students have difficulties in learning certain topics in chemistry, for example, bonding, equilibrium, chemical reactions, electrochemistry, mole concept, and qualitative analysis. Possible reasons why students find such topics difficult include the abstract nature and the inter-relatedness of the concepts involved, the need to shift between four representation systems, and the involvement of process skills. A sound starting point for the teaching and learning of a difficult topic would be the clarification of the knowledge base that is required for the topic. Lists of conceptual and propositional knowledge statements and facts, process skills and metacognitive strategies, as well as concept maps should be drawn up to define the content framework for the topic. This would help teachers and learners to know what exactly is required for the topic. In this paper, the authors describe how they define the content framework for secondary chemistry qualitative analysis to facilitate the teaching and learning of qualitative analysis.
      2007  460
  • Publication
    Open Access
    Word Juxtapoz: An innovative tool for promoting interest in science education
    (1999-12)
    Subramaniam, R. (Ramanathan)
    ;
    Goh, Ngoh Khang
    ;
    ;
    Chia, Lian Sai
    Word Juxtapoz, a new approach which uses words, letters, numbers or symbols juxtaposed in a particular manner or format to convey ideas is shown to be useful for promoting interest in physics, chemistry, mathematics and biology. The juxtaposition of seemingly incongruous elements in the Word Juxtapoz puzzles fosters a scientific way with words that becomes apparent only with some understanding of the topics covered. The etymoloical basis of such puzzles is discussed as well as the methodology for generating the puzzles. Several examples are used to illustrate the approach, and their potential benefits enumerated for teachers and students.
      572  507
  • Publication
    Open Access
    Thinking and understanding in qualitative analysis practical work
    (2002) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
    ;
    Treagust, David F.
    Students find qualitative analysis practical work difficult and are often uncertain about what they are doing in the laboratory. Students need to have tacit knowledge of the phenomena and reagents involved in qualitative analysis to understand the reactions that occur and the results that they get doing the experiments. Teachers also need to make explicit the links between the theory that students learn in class and the practical work that students do. In addition, teachers need to model the metacognitive strategies that students need in qualitative analysis practical work.
      120  1291
  • Publication
    Open Access
      118  154
  • Publication
    Open Access
    Do school texts promote the understanding of inorganic chemistry qualitative analysis?
    (SEAMEO RECSAM, 2001) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
    This paper describes the analysis of two commonly used secondary chemistry textbooks and two practical workbooks in Singapore to determine if the contents present are consistent with the concepts and prepositional knowledge, identified by the authors, as essential for the learning and understanding of O-level qualitative analysis. It was found that none of the textbooks and workbooks explicitly highlighted all the reactions involved in the procedures in qualitative analysis. The omission was likely to give students incomplete or little understanding of qualitative analysis, resulting in students adopting a cookbook understanding of qualitative analysis, resulting in students adopting a cookbook approach to qualitative analysis practical work.
      362  231
  • Publication
    Open Access
    Students’ understanding of acid, base and salt reactions in qualitative analysis
    (The Association for Science Education, 2003-03) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
    ;
    Treagust, David F.
    A two-tier multiple-choice diagnostic instrument was used to determine 915 grade 10 students' (15- to 17-year-olds) understanding of the acid, base and salt reactions involved in basic qualitative analysis. The results showed that many students did not understand the formation of precipitates and complex salts, acid-salt/base reactions and thermal decomposition involved in qualitative analysis. This indicated that the usual method of teaching the topic might be ineffective in fostering its understanding. In response to this, an instructional package which emphasised the three levels of representation of the reactions was developed.
      260  1901
  • Publication
    Unknown
    Students' conceptions of ionic bonding
    (2000) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
      90  573
  • Publication
    Open Access
    The development of a two-tier multiple choice diagnostic instrument to identify secondary three and four students’ (14-17 years old) alternative conceptions in chemical bonding
    (1999-12) ;
    Goh, Ngoh Khang
    ;
    Chia, Lian Sai
    ;
    Treagust, David F.
    Chemical bonding is a topic which many secondary students find difficult to understand. The concepts in chemical bonding are abstract; one cannot see an atom, its structure and how it reacts with other atoms. Therefore there is great potential for the formation of alternative conceptions as students try to derive meaning from what is written in the textbooks or what is said by the teacher. Thus teachers need to be able to detect and diagnose the alternative conceptions of their students so that they can challenge these alternative conceptions, and help the students to acquire scientifically acceptable ones. Methods used to determine students’ understanding of concepts include concept mapping (Novak, 1996), interviews (Carr, 1996) and multiple choice diagnostic instruments (Treagust, 1988, 1995). However, multiple choice diagnostic instruments are more readily administered and scored than the other methods, and thus are particularly useful for classroom teachers. This paper describes the development of a two-tier multiple choice diagnostic instrument to identify Secondary Three and Four students’ alternative conceptions in basic chemical bonding.
      432  223