Sir, are we doing an experiment?

Recently, the following tweet came across my feed from Adam Boxer, head of science at TTA, related to evidence for the effectiveness of practical learning in improving educational outcomes.

So what does an effective practical look like in science education? Having observed and taught a large number of lessons involving practical work, most experiments are designed to reinforce theory, not the process of running a scientific experiment. The implicit assumption appears to be that students will pick up a tacit understanding of what it means to plan and conduct ‘scientifically’ and therefore is not made explicit in instruction (Donnelly et al., 1996). This suggests as science educators we need to develop models of practice in the use of practical work that more effectively integrates theoretical and procedural understanding. 

The expectation at present is that students will learn theoretical ideas through practical activities. The learning of scientific ideas is usually a key learning objective of a lesson. This, however, is usually coupled with the absence of any planning of how students might learn such ideas from what they did and observed. Due to curriculum time constraints, little time is devoted to supporting the students’ development of ideas. 

This has been shown in the emergence of ‘discovery-based’ science teaching, especially in junior science—to expect that the ideas that are intended for students to learn would ‘emerge’ from the observations (Solomon, 1999). This approach has an underlying epistemological flaw and the practical problems to which it leads, have long been recognized (Driver, 1978). The flaw is that the learning experience is not identical to the structure used in science. Gardner (1972) defines the structure as the pathways of inquiry that scientists use, what they mean by verified knowledge, and how they go about this verification.

Explanations do not ‘emerge’ from observations, no matter how carefully these are guided and constrained. Science involves an interplay between ideas and observation. One role of practical work is to help students develop links between observations and ideas. This requires the introduction of these ideas. Practical lessons need to be designed to stimulate an interplay between observations and ideas. Even if these links are developed in subsequent lessons, the observations that are made need to be interpreted in the light of the theoretical framework of ideas and models.

Practical work encompasses a wide range of activities with widely differing aims and objectives (Le Maréchal & Tiberghien, 1999). It does not make sense, therefore, to ask whether practical work, in general, is effective. We need to find a way to evaluate a particular task for its effectiveness, one model, to do just that has been proposed by Millar et al. (1999) (see below).

The starting point is the learning objectives—what the teacher expects the student to learn, this could be process or theory. The next stage of the model asks what the students actually do as they undertake the task. As any science teacher will tell you, this may differ to a greater or lesser extent from what was intended. For example, the students might not understand the instructions, or they may understand and follow them but be prevented by faulty apparatus from doing or observing what was intended. The final stage of the model is then concerned with what the students have thought they have learned as a consequence of undertaking the task.

The model helps answer if the practical task is effective. Does the task effectively match what the teacher intended students to do to what they actually do and does the task match between what the teacher intended the students to learn and what they actually learn? 

The fundamental purpose of practical tasks in school science is to help students make connections between what they observe and the abstract ideas that help explain them (Brodin, 1978). Tiberghien (2000) characterizes practicals as trying to help students make links between two ‘domains’ of knowledge: the domain of observations and the domain of ideas (see below). 

A majority of school science practical tasks deal only, or mainly, with the domain of observations. Combining the two-level model of effectiveness with this two-domain model of knowledge allows the development of a framework presented in Table 1 for the effectiveness of a given practical task. 

Table 2 shows how it might apply to a practical task on electric currents in a parallel circuit, where the teacher’s aim is that students should develop their understanding of the scientific model of current as moving charges. If the teacher’s focus were instead on developing students’ understanding of how to deal with ‘messy’ real data, then observation domain thinking would focus on the actual observations and data collected, whereas idea domain thinking would see these as an instance of more general concepts like measurement error or uncertainty. 

A possible objection to this theoretical framework is that all observation involves a theory, so there is no clear distinction between observations and ideas. All observations at some level require a theory to explain their existence, but I would argue that the extent of how they require a theory differs considerably and that the theory with which a given observation is based around is often not at issue or under test in the context in which the observation is being made. The distinction between observations and ideas is valuable and an important one in analyzing the effectiveness of practical tasks.

As regards implications for practice, the two-domain model is a useful tool for teachers in thinking about practical work. First, it draws attention to the two domains of knowledge involved and their separateness. Second, it provides a means of assessing the ‘learning demand’ of the task in relation to cognitive load theory. Leach and Scott (1995, 2002) have developed the idea of learning demand to discuss teaching and learning in science. The learning steps that students take in some activities make significantly greater cognitive demands than others. When looking at practical activities, there is a substantial difference in learning demand between tasks in which students make observations or manipulate a piece of equipment compared to tasks where students make links between the domains of observations and of ideas. The ability of teachers to differentiate between tasks of relatively low learning demand and those where the learning demand is much higher would allow them to identify where greater levels of support are required for learning to occur.

In summary, ‘doing’ science will not lead to the students ‘learning’ science unless they are provided with a ‘scaffold’ which provides the initial means by which students are helped to view the observations in the same ‘scientific way’ as a trained practitioner in science (Ogborn, Kress, Martins, & McGillicuddy, 1996). So discovery learning in of itself is not effective. This position is supported by Lunetta (1998) who has argued that inquiry alone is not sufficient to enable students to construct the complex conceptual understandings of science. If students’ understandings are to be linked to those of accepted science, then the intervention of a teacher is essential. (p. 252) The issue, then, is the form that this intervention the teacher takes, and the extent to which this intervention is built into the practical task.  Given the clear importance in any practical task of helping the students to do what the teacher intends in the limited time available the following is suggested. First, practical tasks based around ‘recipes’ will still have a significant role to play. However, the tasks need to be coupled with a division of the practical lesson time more equitably between ‘doing’ and ‘learning’.

The reason for this second point is the size of the cognitive challenge for students in linking their observations to a framework of ideas. This division, of course, does not have to be rigidly separated, but teachers need to devote a greater proportion of the lesson time to helping students use ideas associated with the observations they have produced, rather than seeing the successful production of results as an end in itself. Using the framework outlined in this post could help teachers to make improved evaluations of the effectiveness of their current practice, perhaps stimulating review and revision of some of the practical activities they use in ways that could significantly increase the effectiveness of their teaching of science.

References

Donnelly, J., Buchan, A., Jenkins, E., Laws, P., & Welford, G. (1996). Investigations by order. Policy, curriculum and science teachers’ work under the Education Reform Act. Nafferton, UK: Studies in Education Ltd. 

Driver, R. (1975). The name of the game. School Science Review, 56(197), 800–805. Feyerabend, P. (1988). Against method. London: Verso.

Gardner, P. L. (1972). Structure‐of‐knowledge theory and science education. Educational Philosophy and Theory, 4(2), 25-46.

Leach, J., & Scott, P. (1995). The demands of learning science concepts: Issues of theory and practice. School Science Review, 76(277), 47–52. 

Leach, J., & Scott, P. (2002). Designing and evaluating science teaching sequences: An approach drawing upon the concept of learning demand and a social constructivist perspective on learning. Studies in Science Education, 38, 115–142.

Lunetta, V. N. (1998). The school science laboratory: Historical perspectives and contexts for contemporary teaching. In K. Tobin & B. Fraser (Eds.), International handbook of science education (Part 1, pp. 249–262). Dordrecht, The Netherlands: Kluwer. 

Millar, R., Le Maréchal, J.-F., & Tiberghien, A. (1999). ‘Mapping’ the domain: Varieties of practical work. In J. Leach & A. Paulsen (Eds.), Practical work in science education—Recent research studies (pp. 33–59). Roskilde/Dordrecht, The Netherlands: Roskilde University Press/Kluwer. National Curriculum Council. (1989). Science in the national curriculum: Non-statutory guidance. York, UK: National Curriculum Council.

Ogborn, J., Kress, G., Martins, I., & McGillicuddy, K. (1996). Explaining science in the classroom. Buckingham, UK: Open University Press.

Solomon, J. (1999). Envisionment in practical work. Helping pupils to imagine concepts while carrying out experiments. In J. Leach & A. Paulsen (Eds.), Practical work in science education— Recent research studies (pp. 60–74). Roskilde/Dordrecht, The Netherlands: Roskilde University Press/Kluwer.

Tiberghien, A. (2000). Designing teaching situations in the secondary school. In R. Millar, J. Leach, & J. Osborne (Eds.), Improving science education: The contribution of research (pp. 27–47). Buckingham, UK: Open University Press.