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A chemical in the mouth

Posted on Feb 08 2013 by Pauline Ross

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Experiment Overview

The practical class is integral to the process of teaching and learning in the Sciences (Hodson, 1988; 1990; 1993).  Traditionally, it is viewed as the place where students develop some of the expertise of professional scientists, such as manipulative skills, experience in designing experiments and conceptual understanding (Hodson, 1988, 1993; Dawson, 1994).  Commonly, University educators structure the practical laboratory so that the students are directed to follow a series of specific steps, rather like the steps in a recipe or cookbook (Fraser and Deane, 1999).  Although students may develop manipulative and technical skills this way, it is unlikely that they will develop a view that Science is a process of inquiry nor gain better understanding of concepts.  Indeed, students can leave practical classes more confused about the concept under investigation than when they arrived (Beaver 1999).  This is particularly the case when the ‘noise-to-signal’ level is high. ‘ Noise’ here is defined as the multilayers of information that students need to assimilate at once in a practical laboratory , rather than the physical 'sound' in the practical laboratory which may also be high.  Alternatively,  the practical lesson could be based on macroscopic observations which require a microscopic or submicroscopic understanding (Hodson, 1993).  To provide students with the experience of Science as a process, inquiry, investigations and problem-solving need to be a major part of learning and teaching in the sciences.  Then there will be the potential to increase conceptual understanding, connecting doing and knowing, but moreover get  students  putting the information in a structure which is meaningful. 

If this is to occur, then each practical laboratory needs to provide students with sufficient time to think, discuss, make plans, do experiments, reflect and discuss their results.  Although the value of student investigations in the laboratory has been recognised for some time (e.g. Nuffield) and termed ‘discovery’ learning by some proponents (Schwab, 1962), in recent years this strategy has been used for only some types of biology investigations, most commonly with fieldwork exercises or for some laboratory experiments which can be easily reformulated.  Antagonists of such ‘inquiry”  ‘discovery’ approaches argue they are fraudulent, requiring students to reveal the truth of theorems which had often taken scientists an entire life time to elucidate or were the result of centuries of work and thought e.g. such as some of the principals of motion, matter and energy, or  the molecular nature of photosynthesis (Ross and Tronson 2007).  They  argued that the obsolete epistemology of inquiry was not only responsible for the shortfall in expectations of the major effort to improve science education in the 1950s and 1960s, but that inquiry-orientated science was the major barrier in the way of revolutionary improvement of science education (Novak, 1988).  Novak (1988) lamented the lack of evidence of learning gained in laboratories where enquiry learning occurred. He stated that students gained little insight into either key science concepts or process in laboratories because of an instructional misconception that physical activity and cognitive gain were somehow equivalent (Hodson, 1990; 1993; 1998).  Others agreed, and inquiry activities undertaken in laboratory work came under increasing scrutiny for their ineffectual influence for dealing with students misconceptions which left unchallenged scientifically unacceptable conceptual understandings (Novak, 1988; Solomon, 1988; Hart et al., 2000). 

Although the arguments for moving away from ‘discovery’ learning are compelling, equally compelling arguments can be made for the value to students of decreasing the number of practical laboratories with a cook-book like approach.  A cook-book approach may be time efficient and cater for students with limited laboratory skills, but the danger is that, if it is the only approach used in a whole practical course, it portrays a Science as a set of isolated, “correct”  facts to be learnt If this is the only experience students have in the laboratory, they are allowed very little room to make mistakes and learn from these by needing to work out for themselves ‘why’ things ‘went wrong’.  Philosophically, treating students as passive vessels to be filled only serves to reinforce Science as static and deterministic.  Educationally, it gives students little opportunity to engage in the learning process and develop skills in thinking.  Students do require a fundamental base of biological knowledge, yet they also need be involved in the dynamic process which is Science, develop skills in thinking, develop confidence and be motivated by the process.  The dilemma for the University educator is to design teaching and learning strategies in the laboratory which encourage students to be mentally active.  Here I  argue that many ‘tried and true’ practical exercises  are tired and  tortured and fall short of achieving the objectives to which they aspire because of their structural framework .



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