- Revisiting big ideas: range, size and identification
Science is complex. How can we expect students even to begin to understand the vast array of ideas, theories and principles that seem to be necessary to grapple with this complexity? A clue to how this might be possible comes from listening to experts in science explaining to non-experts how the world works. They identify the (usually very few) key ideas which explain a phenomenon, cutting through the distracting detail. For example, a physicist can show how just two key ideas (Newton’s second law and the universal law of gravitation) explain how satellites and space craft are kept moving round the Earth and enable us to calculate the velocities needed to keep these objects in orbit or bring them down to Earth.
We are not suggesting the key ideas can be directly taught, or denying that building the relevant ideas involves bringing together many smaller ideas from a range of learning experiences. But we are convinced that ensuring that these learning experiences are linked to key ideas can provide the understanding that all students need to make sense of what they observe in the world. Moreover, as discussed earlier, this understanding can enable them to grasp what is involved in science-based decisions that affect their own and others’ wellbeing. Whether or not these potential benefits are realised will depend, of course, on the choice of ideas to be included. Two key decisions concern: Range – whether to include scientific attitudes and dispositions towards science and what are variously called skills, practices, competences or capabilities as well as core scientific ideas. Size – how broad a compass of phenomena the ideas should explain, recognising that the larger the idea, the more distant it is from particular phenomena and the more abstract it therefore appears to be.
We are not suggesting the key ideas can be directly taught, or denying that building the relevant ideas involves bringing together many smaller ideas from a range of learning experiences. But we are convinced that ensuring that these learning experiences are linked to key ideas can provide the understanding that all students need to make sense of what they observe in the world. Moreover, as discussed earlier, this understanding can enable them to grasp what is involved in science-based decisions that affect their own and others’ wellbeing. Whether or not these potential benefits are realised will depend, of course, on the choice of ideas to be included. Two key decisions concern: Range – whether to include scientific attitudes and dispositions towards science and what are variously called skills, practices, competences or capabilities as well as core scientific ideas. Size – how broad a compass of phenomena the ideas should explain, recognising that the larger the idea, the more distant it is from particular phenomena and the more abstract it therefore appears to be.
Range
Science education is concerned with more than conceptual understanding, as expressed in the principles relating to aims (page 7). In addition to the ideas that explain what is going on in the world, science education has other aims, including developing:
understanding of the nature of science
the capabilities needed to engage in scientific activity
scientific attitudes and informed attitudes towards science
appreciation of the relationship of science to other subjects, particularly technology, engineering and mathematics.
Whilst acknowledging that science education should lead to these various outcomes, our decision to focus on big ideas of science and about science follows from our view that ideas play a central role in all aspects of science education. The development of understanding is a common factor in all science education activities. Science inquiry capabilities, or practices, and scientific attitudes and dispositions are developed by engaging in activities whose content involves science understanding; otherwise the activities can hardly be called scientific. Although we may emphasise and reinforce behaviours relating to, for example, cautious attitudes to interpreting data, or what is needed to plan a scientific investigation, the activity will also relate to one or more scientific ideas, for these attributes are not developed in isolation from scientific content. This argument does not negate the value of establishing lists of attitudes and abilities and explicitly working towards them at the same time as developing some conceptual understanding, but it reflects the principle that all science activities should deepen understanding of scientific ideas as well as having other possible aims.
Understanding the nature of science
We also want learners to understand the processes of scientific activity as well as the ideas to which it leads, that is, to know how the ideas that explain things in the world around have been arrived at not just what these ideas are. Indeed, it is hard to envisage separating knowledge about scientific activity from knowledge of scientific ideas. Without knowing how ideas were developed, learning science would require blind acceptance of many ideas about the natural world that appear to run counter to common sense. In a world increasingly dependent on the applications of science, people may feel powerless without some understanding of how to evaluate the quality of the information on which explanations are based. In science this evaluation concerns the methods used in collecting, analysing and interpreting data to test theories. Questioning the basis of ideas enables all of us to reject claims that are based on false evidence and to recognise when evidence is being used selectively to support particular actions. This is a key part of using scientific knowledge to evaluate evidence in order to make decisions, such as about the use of natural resources.
Capacity to engage in scientific inquiry
Participation in scientific inquiry enables students to develop ideas about science and how ideas are developed through scientific activity. The key characteristic of such activity is an attempt to answer a question to which students don’t know the answer or to explain something they don’t understand. These may be questions raised by students but, since it is not realistic for all students always to be working on their own questions, it is part of the skill of teacher to introduce questions in a way that students identify them as their own. The answer to some questions can be found by first hand investigation, but for others information is needed from secondary sources. In either case the important feature is that evidence is used to test ideas and so the understanding that results will depend on what evidence is collected and how it is interpreted. Therefore, capabilities involved in conducting scientific inquiry have a key role in the development of ideas and the pedagogy that supports the development of big ideas must also promote the development of competence and confidence in inquiry. We return to this in Section 5.
The STEM context
The question about the relationship between science, technology, engineering and mathematics (STEM subjects) arises because understanding situations in daily life often involves combinations of these subjects; indeed much of what is referred to as ‘science’ in everyday life is better described as technology or engineering. Greater integration of STEM in educational programmes would afford opportunities for a better match of teaching and learning to practices in the work place and research settings and would be more likely to capture students’ interest and engagement. A further argument for some degree of integration follows from the cognitive research that suggests connected knowledge is more readily applied in new situations than separate pieces of knowledge. However, what little research there is on the effects of integrating science with other subjects suggests that, at school level, it can be counter-productive to attempt to make connections if the ideas in each domain have not been securely learned. Rather than trying to teach the STEM subjects in an integrated manner, the advantages of bringing them together would be better secured by curriculum planning that coordinates related themes and topics.
Size
The issue of making connections across domains also arises in the context of addressing the question: how big should big ideas be? We identify big ideas of science as ideas that can be used to explain and make predictions about a range of related phenomena in the natural world. Explanatory ideas can come in different ‘sizes’: for any idea that applies to a few phenomena there is generally a bigger one applying to a larger number of related phenomena and which, in turn, can be subsumed into an even bigger, more comprehensive idea. For example, the phenomenon of one substance dissolving in another, such as sugar dissolving in water, is ‘explained’ by young children in terms of the sugar having disappeared. This naïve idea soon has to be adapted to account for the evidence that the sugar is still there in the water and then becomes ‘bigger’ to explain why some things do not dissolve in water and some colour the water but cannot otherwise be seen. Then, the idea of dissolving needs to be enlarged further to apply to other liquids and solids. This explanation might then be connected with how other phenomena are explained in terms of interactions at molecular levels. The process of connecting ideas together to form bigger ones could continue in theory until there is a very small number of overarching concepts or even a single one that explains everything. Such ideas would necessarily be highly abstract, distant from actual experiences, and less useful for explaining these experiences than ideas that are more obviously linked to particular events and phenomena. They do not merely cut across subject discipline boundaries, as do ideas described as interdisciplinary, but completely obscure discipline boundaries and are better described as transdisciplinary. They include ideas such as system, symmetry, causality, form and function, and pattern. Our decision to position big ideas at the interdisciplinary level, below the level of overarching transdisciplinary concepts, was taken by considering the needs of learners and their teachers. Discussing transdisciplinary ideas may be appropriate for the most able 18 year olds but otherwise is more appropriate for undergraduates and beyond. For the learner at school, who may or may not be embarking on a science-based career, the rather less general ideas with more obvious links to their experience seem most useful. It is the big ideas at this level that science education should aim to help all learners to develop, keeping in mind the difference between a statement of goals and how these goals are best achieved. Further breakdown into a range of smaller ideas is, of course, possible but risks losing the connections between the smaller ideas that enable them to merge into a coherent big idea.
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