The teaching of critical thinking in physical science

M.Ed.The traditional method of instruction was based on the assumption that knowledge could be transferred intact from teacher to learner. This led to the lecture method being the most popularly used by teachers to transfer information. Learners also became too dependent on the teacher and ended up lacking in basic critical thinking skills and resourcefulness. Learners are increasingly finding it difficult to know why a particular reason is correct or incorrect. They also find it difficult to follow a logical argument used to arrive at a particular conclusion and subsequently find it difficult to follow the lesson. This is confirmed by Muller (1998:2) when he says: "Die heelwat laer tellings wat Suid-Afrikaners behaal het, dui op n gebrek aan begrip en vaardighede in wiskunde en wetenskap. Die land se matrieks het ook baie swak gevaar wanneer hulle kreatief antwoorde moes konstrueer". Performance and interest in science, world wide, are declining as learners find science to be a difficult subject. Bodner (1989:27) who says: "only 2% of the college-level students in the US that graduate are physics or chemistry majors" supports this. Learners entering tertiary institutions are generally considered ill-prepared for the task ahead. The problem of critical thinking is not restricted to the South African context alone, as stated by Kistner, (1988:123) who says: "All over the world academics are complaining that students entering universities cannot cope with standard textbooks, follow sustained arguments, or write coherent essays".At a National Science Teachers' Association (NSTA) in Washington, teachers asked what it was that they were supposed to do so that their learners could be considered ready for science at college level. The reply was that they should be taught to think and solve problems. Then they will learn to be subject specialists at university (Zielinski & Sarachine, 1993:1). They go further to state that a survey of first-year college learners in science pointed to a need for more creative/critical thinking in secondary science curricula. Learners who find it difficult to follow logical arguments become demotivated and lose interest in the subject. It is important for educators to understand the root cause of learners inability to cope with subjects like mathematics, science and technology, which require a coherent logical argument. Brookfield (1991: tape) points out that we often make inherent assumptions in our daily lives which are so embedded in us that it is even difficult to detect them. One of the assumptions we make as teachers is to take it for granted that our learners understand us and that they should think like ourselves, because we teach them. Brookfield goes further to say: "we have to make an effort to be aware of our assumptions, name them and assess their validity".Lozauskus and Barell (1992:45) state that science teaching should emphasise creating risk-free settings where students can explore relationships among concepts, pose puzzling questions and research answers. Allen (1987:139) gave a conclusive reason why learners do not achieve this important aspect of learning: "Teachers seldom encourage students to examine evidence and almost never give them the opportunity to explore lines of reasoning. Rather they focus on getting students to accept teacher statements as truth". We ignore the fact that we only teach the prescribed syllabus without diverging a little to teach learners how to analyse, criticise and even ask how they have interpreted what we have said, so as to check if what we have taught has been understood the way it was we intended. In other words teach them how to think critically. Learners develop a negative attitude towards a subject if they do not cope. This is supported by McMillan and May (Cherian, 1996:1) who say: "the objective of any science curriculum includes fostering favourable feelings toward science as well as imparting knowledge". Each aspect of education is enhanced by means of content, which emphasises that particular aspect. Thus, it is then imperative that the content we teach should be geared towards aiding the development of critical thinking, if we wish to assist our learners with critical thinking. If this is what we expect of our learners then it should receive attention from science educators. "The complex nature of the rapidly changing society demands critical thinking skills from all learners. If they lack these skills, learners might be unable to focus on the fundamental and essential aspects of the course content of the various subjects being studied" Fourie and Nel (1994: 18).Teachers do not keep track of the latest developments in their respective subjects and do not renew their approach at all times accordingly. Some teachers do not involve learners in their own learning. Consequently learners end up disliking the subject. This is an undesirable outcome. Science instructors still emphasise computation before concepts (Barba, 1995:12). This makes learners unsuccessful in science and thus denies them entry into the field of science, which is influenced to a large extent by success in science. There is too much focus on completing the syllabus (if ever). Educators work under undue pressure to prepare learners for the examination. Completing the syllabus is traditionally considered an important aspect so as not to disadvantage the learner in examinations - especially if the learner is going to write a public examination. In the process, important aspects of learning such as understanding concepts and critical analysis are overlooked. A teacher's performance is to some extent measured by his ability to complete the syllabus rather than the quality of work done. The investigator hopes that this study will provide a useful base for improving the teaching/learning of science by finding out if it is possible to teach learners to think critically and, if so, give leads on how this can be achieved