Build NoS into biology programmes15/10/2012
Science education researchers have identified key aspects of NoS that should be incorporated into science learning in school programmes, writes Kate Rice.
Students should understand that scientific knowledge is seen as “tentative, empirically based, subjective, partly the product of human inference, imagination and creativity, socially and culturally embedded, involving a combination of distinct observations and inferences, and also describing both the functions of and the relationship between scientific laws and theories” (Abd-El-Khalick, Bell & Lederman, 1998, p.418). Thus, teaching and learning programmes need to provide experiences that develop the critical, creative, empirically-based perspectives on scientific knowledge and knowledge construction in biology concepts.
Students should be provided with a range of practical experiences that develop a clear understanding of both the myth of the universally accepted scientific method, and the nature and assumptions that underlie the development of scientific theories they encounter in biology. This must be combined with an understanding of the relationships between scientific concepts of hypotheses, theories and laws, and perceived realities, as well as the tentative nature of scientific reasoning evident in biology concepts.
Exploring concepts in ecology can allow debate on the creative nature of explanations developed by scientists to explain some observations of New Zealand’s unique flora and fauna. On field trips in native forests, students can be introduced to the divaricating morphology of shrubs from unrelated genus and species. A follow-up discussion can be introduced based on the suggestion that the predominance of divaricating habit among NZ shrubs from unrelated plant species was a morphological adaptation that provided protection for their fruits to mature, preventing grazing by large herbivorous birds that fossil evidence indicates coexisted with such plants in the NZ environment.
Looking for patterns
Many investigations carried out in biology are not fair tests, but pattern seeking. In biology, investigations deal with living organisms and their systems, and these do not allow for easy manipulation and/or control of factors. An example is investigation using potato chips in different concentrations of sucrose. Each chip can be cut to roughly similar dimensions, but water, starch and sucrose content of each could differ across the chips dependent on cultivar, storage conditions, age of potato etc.
For senior students, the investigation to consider the effect of sucrose on the potato chips needs to be structured so they consider any natural variation of the potatoes, possible sample size, observations they might make, and how these link to possible causes as they develop their investigation. When they suggest a pattern from their results, they also need to understand that they have been modelling a system. The teaching relating to investigations needs to be explicit so that students understand that there is more than one way to investigate. Creating and solving a punnet square is a valid form of investigation where findings are linked to scientific theories through modelling. In a similar way, classification is a technique used by not just scientists, but also in students’ daily lives to help them make sense of observations. In classifying, a range of objects are arranged into manageable groups because we have recognised particular features or processes that distinguish between the organisms or their systems. The recognition that this classification is “subjective, partly the product of human inference, imagination and creativity” may be a novel approach to introduce in Years 11 and 12 Biology. However, it is vital for students to engage with classification and identification of features of organisms in this way so that they understand the tentative nature of scientific knowledge, and can understand why as more information is gleaned through improved techniques, these systems and classifications may change.
When exploring life processes in Years 11 and 12, the focus should be on students making a series of careful observations, possibly over a period of time. To be effective, students need to make decisions about what to look for, the details to record, and how to record their observations, how many to make and how often. The teacher’s role is to build student capability to make effective observations, guiding them to build in-depth information on a carefully defined exploration. Such exploration requires modelling and scaffolding by the teacher through effective questions that identify aspects for students to ‘notice’.
A possible situation for exploration could be the reproductive process of a grass, or support and movement of an arthropod. Exploration of natural phenomena through careful observation is another type of investigation. The findings should be related to scientific theories, or models, that students have already begun to understand.
Biology makes use of models to help explain systems operating in the living world. Such models are based on creativity and inference. To be effectively used in teaching, students need to be engaged with both the model and the theoretical concepts the model is seeking to represent.
Opportunities must be provided for students to question and discuss both the model and the theory, and use the model to provide responses to problems or examples relating to the theoretical concept. For example, a bell jar and balloons’ model to represent the inspiration of mammals clarifies the role of the diaphragm, but discussion is needed to identify the role of the intercostal muscles in the process. Such a model also does not clarify the gas exchange process, and is modelling only part of the whole respiration system. This may be useful, but must be linked with modelling and discussion of gas exchange at the surface of alveoli in the lungs and the processes involved in cellular respiration.
An alternative approach to using models is to challenge students to produce their own model of a system they are familiar with to share their understanding of the system with their peers.
Introducing and emphasising the range of different approaches to investigation that can be used to extend students’ knowledge in biology will help develop their understanding of the relationship between investigations and scientific theories and models.
Watch out for: BEANZ Level 3 regional workshops during Term 3 or 4.
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- Abd-El-Khalick, F., Bell, R.L., & Lederman, N.G. (1998). The nature of science and instructional practice: Making the unnatural natural. Science Education, 82(4), 417-436.