TEACHERS DEMONSTRATION METHODS OF TEACHING AND STUDENTS ACADEMIC PERFORMANCE IN BIOLOGY
The issue of using demonstrations (to be defined later) in a chemistry classroom has often been discussed in the research literature (Hofstein & Lunetta, 1984; Bare, & Andrews, 1999; Thompson & Soyibo, 2002). Among the questions posed in the literature, we found the following: Are demonstrations as effective as individual students’ experimentations? Do demonstrations promote the understanding and internalization of scientific concepts? Can demonstrations develop students’ thinking skills? And what conditions are needed to make teachers’ demonstrations more effective than individual students’ experimentations? Although lecture demonstrations have been conducted in chemistry classrooms for a long time, little research exists that documents the frequency that such demonstrations are employed or their effect on learners’ motivation and performance (Price & Brooks, 2012; Odom & Bell, 2015). Shakhashiri (1992) remarked that “Educators have often searched for various ways to teach science”. The use of demonstrations is one of numerous pedagogical interventions that have been adopted for enhancing students’ interest. Experiments and demonstrations that confirm a physicochemical phenomenon such as illustrating chemical processes by light-sticks (Kuntzleman, Rohrer & Schultz, 2012) can be used to facilitate understanding certain chemical concepts, for example, acid-base reactions, redox reactions, fluorescence, quantum chemistry, and thermodynamics.
A demonstration involves illustrating a point in a lecture or a lesson by means of something other than routine visual aids or other means of instruction. A demonstration in chemistry may be defined as a pedagogical event whose objective is to illustrate a scientific concept (Taylor, 1988). This definition can be broadened and divided into three categories: (1) Visual aids used in an unusual manner, for example, teachers and students using body movements to illustrate acid/base chemistry and oxidation/reduction; another example would be Lomax’s (1994) kinetic class, in which movement is used to reinforce the concept of chemical transformations. (2) Analogical demonstrations, in which one uses a phenomenon whose behavior is similar in relevant aspects to that of the scientific concept under discussion. A good example of this would be the use of steel balls on the glass cover of a watch to illustrate the density of atoms in a pseudo-metallic structure. (3) Real experiments, which are the most common type of demonstration: Shakhashiri presents numerous examples in his five published books (1983, 1985, 1989, 1992 & 2011). According to Chiappetta and Koballa (2002) and Shakhashiri (1992), well prepared and properly presented demonstrations have the potential to enhance students’ understanding of chemistry concepts. Similarly, Hofstein and Lunetta (1982, 2004), in their comprehensive reviews, came to the conclusion that demonstrations have the potential to enhance learning, motivation, and attitudes.
Gardner (1978) suggested that demonstrations may enable learners to evoke the “wow” experience. This consequently can increase their curiosity and enhance their reasoning abilities. In addition, it may have an impact on students’ achievements (Gerber, Cavallo & Marek, 2001). Moreover, there are occasions in which teachers’ demonstrations are educationally more effective than are students’ own experimentations (Hofstein & Lunetta, 2004, Lunetta, Hofstein & Clough, 2007). Although research on the effectiveness of demonstrations has been conducted since the early 1960s, most of the studies were general, namely, comparing students using experimentations with teachers’ demonstrations, covering a wide range of topics and concepts. A number of research papers reported clear benefits when demonstrations are used for teaching the sciences. In a study on college introductory physics courses, Buncick, Betts, and Horgan (2001) found that demonstrations encourage generalization because they promote active participation on the part of the students. An elevated level of student attention and involvement in tasks has also been reported for demonstrations carried out in high-school chemistry courses. For example, Meyar et al. (2003) have shown that demonstrations encourage student involvement, since they are less teacher- oriented and give students an opportunity to produce questions and to become more active in the learning process. This in turn can motivate students to undertake an initial inquiry and also provides a learning opportunity, because it helps create mental links between new and previous learning. In addition, Meyar et al. reported that students can illustrate cognitive strategies by observing the teacher as he thinks out loud while doing the demonstration and as he formulates questions that lead to an explanation of the concepts in question. This may challenge students’ preexisting understanding and can encourage perceptual understanding.
The traditional teaching strategy of using a lecture-type approach may perhaps be favored by those students who are in favor of the didactic methods of learning and who are considered conscientious (Hofstein & Kempa, 1985; Kempa & Diaz, 1995). Demonstrations in use as a teaching strategy may prove beneficial for students with different or special learning needs. It is assumed that, when combined with traditional methods, demonstrations can be effective for low-achieving students with high visual and spatial intelligence but with limited cognitive abilities (Meyer et al, 2003; Rade, 2009; Baddock & Bucat, 2008). Although considerable research has been conducted on the use of demonstrations to teach chemistry, few studies have focused on how effective this method is in promoting cognitive involvement. Hofstein et al. (2005) and Dkeidek, Mamlok-Naaman, and Hofstein (2012) published a study on question asking as a tool for developing high-order thinking skills in the chemistry laboratory. They showed that students in the Jewish sector in Israel ask more questions than their Arab conterparts. This may result from a lack of knowledge in this area, which in turn, may be one of the reasons why it has been so difficult to justify the allocation of teacher time and resources for demonstrations.