Tan, Kim Chwee Daniel

Chemical bonding is a topic which many secondary students find difficult to understand. The concepts in chemical bonding are abstract, so there is great potential for the formation of alternative conceptions as students try to derive meaning from what is said by the teacher or what is written in the textbooks. Thus teachers need to be aware of students’ conceptions of chemical bonding in order to develop teaching strategies to enable their own students to construct ideas of chemical bonding which are compatible with the scientific concepts.

High school students have difficulty in understanding the concepts involved in intermolecular forces. A sound starting point for the teaching and learning of a difficult chemistry topic would be the clarification of the content framework that is required for the topic. Lists of propositional knowledge statements and concept maps should be drawn up to define the content framework for the topic to make explicit the essential concepts of the topic and how these concepts are linked to each other. In this paper, the authors described how the content framework for high school intermolecular forces was developed to facilitate the teaching and learning of intermolecular forces.

Computer games can provide an immersive environment for players (learners) to experience scientific phenomena, reactions and properties according to related theories and laws, and provide a relevant context to assist learners to make sense of scientific concepts involved. Inquiry-based learning is also facilitated as players have to explore, discover, form hypotheses, experiment and make decisions based on outcomes generated in the game in the pursuit of an overall goal. Thus, science-based computer games can allow the player to learn to be a scientist, by thinking and acting as one in the game, instead of merely learning about science. This paper describes the development of a multi-player game, Legends of Alkhimia, and its associated instructional material to facilitate scientific inquiry and the learning of chemistry by lower secondary (Grades 7 and 8) students in Singapore. Challenges faced and lessons learnt in the implementation of game-based learning in the classroom are also discussed.

Grade 10 (15 to 17 years old) students have difficulties in understanding ion-exchange reactions and complex salt formation involved in the tests for cations in basic inorganic chemistry qualitative analysis. Many students believed that when an insoluble hydroxide was produced from the reaction between an unknown cation and a hydroxide ion, a more reactive ion displaced a less reactive ion to form the precipitate. Students also explained that the reaction between several hydroxides and excess alkali as the precipitate dissolved when excess alkali was added because more solvent was added or that no new reagent was added and no further reaction was seen. Possible reasons proposed for such student conceptions included conceptual interference and perceptually-dominated thinking.

This cross-age study sought to determine the extent of secondary students’ (14-17 years old), junior college students’ (16 to19 years old), and graduate in-service teachers and trainee-teachers’ understanding and alternative conceptions of basic inorganic chemistry qualitative analysis. The results from the administration of the two-tier multiple choice Qualitative Analysis Diagnostic Instrument (QADI) showed that there was a statistically significant difference in mean scores across educational levels – as expected, the in-service teachers and trainee-teachers obtained the best results, followed by the junior college and the secondary students. However, the mean scores of the graduates (9.9/19), junior college students (8.1) and secondary students (5.8) showed that they found the QADI difficult. The cross-age study showed that many alternative conceptions were prevalent among the different groups but were consistently held by only a small number of subjects (0-23%) across all contexts examined in the QADI. These results indicated that the subjects might have more than one conception for a particular concept, or had little understanding of qualitative analysis and resorted to guesswork. The present chemistry practical assessment system in which only students’ written reports are assessed and marks mainly allocated to correct observations could be the major factor influencing students’ lack of understanding of QA.

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.

This paper reports the findings of an online survey aimed at exploring the use of dataloggers in learning inquiry science and project work in secondary schools and junior colleges. It examines the type of activities which teachers conduct using dataloggers, the support structures they deem necessary and the difficulties they faced. Out of the 593 Heads of Department (Science) and science teachers who responded to the online questionnaire survey, 394 (67%) have used dataloggers in the last 2 years, mainly in demonstrations and set experiments. The three most important support structures that were listed by the respondents included: supportive laboratory technicians who were able to use dataloggers, training on the use of dataloggers, and instructional material about how to use dataloggers in the curriculum. The difficulties which deterred the respondents from using dataloggers included the difficulty and time taken to set up the datalogging equipment and activities, insufficient computer workstations, and the mishandling of equipment by students. Recommendations about facilitating the use of dataloggers in school include the setting up of laboratories dedicated for datalogging activities, having courses on datalogging for teachers and laboratory technicians, and the preparing curricular materials on datalogging.