What is the task of a science teacher at secondary school in the UK at the moment? As part of the process of learning to achieve good grades in GCSE and A level science subject examinations, our students ought to develop a thorough understanding of what science is as an academic discipline. This is the implication of the National Curriculum documentation for Science. If you are reading this blog as a seasoned classroom practitioner, you may well agree with me that we only achieve this aim in part, because the examinations do not require such a thorough understanding. The National Curriculum and examination syllabus documents typically require us to ensure that our students have a good grasp of the 'scientific method', which is thought to hinge on the key role of controlled experiments in the generation of relevant data. The sum of scientific knowledge increases and it's insights improved through such an experimental process. This is what we mean if we say (though in school, we tend not to use this language) that science is science because it is based on empirical data. A scientist is doing science if they have designed an experiment that generates empirical data, and the conclusions are scientific because the data was obtained empirically.
In classroom language, as recognised by most students, we put it in these terms. From Key Stage 2, students know well that an experiment meets the requirements for being scientific if it is a fair test, that is, that there is just one independent variable and that other (significant/confounding) variables are kept constant. Such controlled variables are either assumed to remain constant, or must be monitored to ensure that they do not change. The experimenter can then measure changes in the dependent variable(s) secure in the knowledge that it will only be changes in the single independent variable that will be causally responsible for changes in the dependent variable(s).
"My independent variable is the one I am investigating the effect of."
"My dependent variable is the one I expect to be affected by the changes in the independent variable."
"Any other variables that could change and affect the dependent variable must be identified and controlled in order to carry out a fair test. If any one of these variables were to change during the investigation at the same time as the independent variable is changing, then my investigation will be invalid; I will not have done a fair test. It won't be scientific.
If, perhaps, a potentially confounding variable does change, I will need to be sure that the size of this change is small and insignificant if I still expect to draw a valid conclusion from my investigation."
At Key Stage 4/5 students are commonly asked to engage in such an analysis and critique of their work, or results they have been given, as it is common for one or more 'controls' to not remain absolutely static. Such questioning typically allows examiners to assess students' grasp of the concept of fair testing and of the nature of scientific enquiry.
Rather as suggested by the poster shown above, Science is presented as a repeating linear sequence, or as a cycle. Most simply, this would be described as beginning with a hypothesis, on which basis a fair test/ experiment would be carried out. Evidence/data/results are collected, suitably presented and then analysed, and finally conclusions are drawn.
The wall poster shown above also includes two prior stages, but these don't particularly reflect specifications in the curriculum documents. The brief outline I rehearsed in the last paragraph does not examine the matter of where the hypothesis on which the new experiment is being based has come from, but this poster recognises that question, and gives 'purpose' [What do you want to learn?] as the first of these initial steps. We are left wondering what the content of this step might be. The next step is more helpful, which gives the idea that science builds up a body of knowledge that is accepted as being more or less certain- as 'facts' if you will- and then through thinking about this prior knowledge, or Research, the scientist, or student, can come to formulate a new hypothesis. Now whether this is really very much to do with school students of science or not (rather than with real scientists), we do therefore get the idea that Science does not progress merely by repeated cycles of hypothesis-forming and fair testing, but that there is an accumulation of (more) certain knowledge and understanding about the natural world in which we can have more confidence. We might go as far as suggesting that students are 'thinking like scientists' in some manner when we role-play this type of activity with them, guiding their thinking, drawing out prior learning, and uncovering their misconceptions, all in ways that are probably vital for their progress against syllabus specifications.
The following flow diagram makes all this clear. It also hints at some helpful complexities. The first two stages of questioning and research are shown as a dialogue. So an important part of science is not being done in the lab (or equivalent) but in the mind(s) of would-be scientists. The aspects of 'working like a scientist' that are covered by the school curriculum focus on the scientific method are not in play here. Is the thinking that scientists and students do in deciding what questions to ask and what research to do an empirical process or conforming to a standardised methodology? Not at all, I think is the answer to that. What are science teachers saying to their students in this area? To what extent is this even a curriculum focus? I think there is likely to be a wide range of practice, and it will be largely ad hoc and inconsistent, if it is done at all. It isn't examined, so it won't be considered of much importance.
There are a small number of curriculum areas where these sorts of mental and imaginative activities are looked at. For example, in the 'History of the Atom' KS4 GCSE focus on the development of models of the atom, from Democritus to Schrodinger. Newland's Octaves, Döbereiner's Triads and Mendeleev's multiple drafts of the Periodic Table. The Kekulé dream serpent image for benzene. Or Darwin's thought experiments incorporating the ideas of Thomas Malthus into his writings on the Origins of Species. Some of these could be considered analysis and drawing conclusions from experimental data, but there is no hard and fast division between the consideration of what conclusions can and should be drawn from yesterday's experiment and what ideas might be conceived that lead to today's new hypothesis. None of the educational charts depict that! The cyclical scientific method is a simplification of processes that are multiple and not singular, and only at best partly understood. This need not be problematic for the students of the philosophy of science, or for school students and their teachers.
There's another branch in the middle of this diagram, where the experiment fails to produce (adequate) data/results/ outcomes. So the scientist returns to the planning stage. But hang on a minute. How is such a decision reached? How is this being decided? What exactly are the judgments being made here about working like a scientist? This area is likely being left underexplored in 'school science'.
Here follows the much more secure and safe territory of 'school science' and the process of 'doing science' that students are told is what scientists are doing. The matter of identifying the problem or question is quickly passed over to the key business of experimental design, implementation and examination of the data that emerges.
And here then is another version of the cyclical method:
At this point I will focus our attention just on one further aspect that is being given a significant place in the scientific method: the development of general theories. This certainly is a key part of 'school science'. It is a common aspect of the classroom dialogue, and the parallel is frequently drawn between what students are learning and the activities of professional scientists. Students are led to draw general conclusions from their (collected, whole class) experimental results, and these are then explained in terms of a larger explanatory narrative that we call a theory. Particular scientific models, ideas and concepts are appealed to in order to explain how the observed phenomena took place. What are the causes and reasons for the phenomenon under study? Which scientific ideas are thought key to explaining how the process(es) take place? Other scientific ideas may well be drawn into the discussion, as such linking of ideas is part of corroborating a theory being given as an explanation. Now this is important. A theory is a larger narrative than the conclusion from one experiment, gaining explanatory power because it is based on the sum of many experimental discoveries. Nevertheless, scientists are not claiming that the explanations we call theories must be watertight to objection. A theory is likely to be accepted as a best-fit effort. There is tolerance of the odd piece of counter-evidence. We are good at telling students that science is provisional, that theories are open to improvement, and, indeed, that one key experiment can produce data that demolishes the existing theory and requires an immediate shift to a new best-fit explanatory theory. This is held up as the strength of science as a discipline that gives unparalleled insight into the cosmos and its workings.
To proceed further, there is a further realisation that is not at all commonplace in the account of science we give to our students. There are aspects of theories that we do not describe or attempt to explain to students in school, and this may well also be true for professional scientists. This leaves the possibility that we allow blind spots to linger in our understanding. Or to put it another way, there can be aspects of our theories that are not so reliant on the experimental data as they really should be. The theory has been constructed from evidence, but also padded out with some imagination. This is described in the literature of the philosophy of science as 'the underdetermination of theories', and is recognised as a theoretical weakness in the scientific process. Now this need not be seen as a fatal flaw, for good practitioners in that field of science should be expected to identify such gaps in our properly grounded theorising and go on to design investigations to fill them.
But I will close here with this conclusion: the part that imagination is accepted to play in the construction of scientific theories is a reiteration of the point made above. Imagination is a non-empirical activity that is accepted as a vital part of the process by which scientific questions are formulated, and here again we see its role in the construction of the theories that are settled on after thorough dialogue in the scientific community, focused on the accumulated experimental data. In this realisation we can confirm that science is a human activity. This does not disqualify the claim that science should be properly characterised as an objective rather than subjective activity- such is the competence of properly exercised expertise in laboratory investigation. Nevertheless, Science must not be considered to be entirely beyond the boundaries of human creation. As scientists, we are adding something to our account of the cosmos, and there will be times when this fact may not be trivial (jumping to conclusions and claims that are simply wrong!). Such cases must be carefully examined to ask whether our Science should be improved, and/or if the areas of doubt show that the question being investigated might not belong to Science but to some other discipline.
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What does the National Curriculum framework say about teaching the scientific method? Here is the relevant section of the 2014 statement for Key Stage 4, with the pertinent phrases shown in red text. Note that Exam Boards then produce their own specifications that map to these criteria, though with some variation.
Science is changing our lives and is vital to the world’s future prosperity, and all students
should be taught essential aspects of the knowledge, methods, processes and uses of
science. They should be helped to appreciate the achievements of science in showing
how the complex and diverse phenomena of the natural world can be described in terms
of a number of key ideas relating to the sciences which are inter-linked, and which are of
universal application. These key ideas include:
• the use of conceptual models and theories to make sense of the observed
diversity of natural phenomena
• the assumption that every effect has one or more causes • that change is driven by interactions between different objects and systems
• that many such interactions occur over a distance and over time
• that science progresses through a cycle of hypothesis, practical
experimentation, observation, theory development and review
• that quantitative analysis is a central element both of many theories and of
scientific methods of inquiry.
