Abstract
Nature of Science is an integral part of scientific literacy which researchers and international policy-making institutions highlight as the purpose of science education. The notions of scientific law, theory and model are crucial for understanding Nature of Science. These notions are better grasped in the historical context of Nature of Science (NoS). For this purpose, appropriate instructional sequences, based on semi-structured interviews, were designed and implemented to investigate whether and how the student teachers of Primary Education can perceive these concepts.
In the present study, an attempt was made, firstly, to investigate the extent to which primary student teachers are able to construct the scientifically accepted views on the notions of law, theory and models in the context of NoS and, secondly, to investigate the adequacy of teaching and learning procedures regarding the notions of law, theory and model and the relations between them in the context of NoS. Identifying and addressing students’ difficulties was crucial to the negotiation of these notions. Teaching sequences were designed and implemented using historical material from Maxwell’s e/m theory.
The empirical research shows that primary student teachers can understand the basic features of laws, models and theories. They can also use these concepts to adequately develop relationships between them. The findings of this study show that students’ learning processes were affected by difficulties in specific subjects. These difficulties were: (a) The definite nature of the law compared to the theory; (b) A scientific law has no limits to its implementation; (c) Distinguishing description from explanation; (d) Theories’ experimental “proof”; (e) Models’ exclusive representational role.
To be more specific, students’ perception that laws are more valid than theories – which is also mentioned by Mackay (1971), Rubba & Andersen (1978), Meyling (1997), Blanco & Niaz (1997), Irez (2006) and Akerson & Hanuscin (2007) – appears to impact on all the issues under discussion. According to this perception, the difference between laws and theories lies in their degree of validity and not in their different functions; as a result, students believe that mature theories become laws. This belief that laws have “absolute power” and do not change then prevents an understanding of the temporary nature of scientific knowledge. When students are gradually confronted with examples of well-known laws which do not apply to the full range of values, they are forced to accept that laws have limits on their power and to conclude that laws of science, as well as theories and models, are subject to control and can change in the light of new evidence. They thus conclude that whether there are some laws in nature which are independent of our knowledge of them or not, the laws made by the scientists are the best possible descriptions of our world and can be changed or corrected if new theoretical or experimental data occurs. After students have overcome this difficulty, they are more ready to develop the relationship between laws and theories.
Regarding students’ difficulty distinguishing between description and explanation, they initially seem to have mixed up Maxwell’s role in the phenomenon of e/m induction and Faraday’s experimental confirmation of that phenomenon. Through historical quotes and appropriate questions, the students ascertained that while Faraday had described the phenomenon of e/m induction, he had not given a complete answer on the mechanism behind it, and that it was Maxwell who did that. Provided with the modern explanation of the phenomenon, which is the e/m wave, students concluded that Faraday had described the phenomenon but had not explained it. The explanation of the phenomenon through the e/m wave is attributed to Maxwell, ending the distinction between description and explanation.
The students’ view that theories are scientifically “proven” was projected when they wanted to justify the scientific character of theories and to focus on the contrast between theories and laws, which they consider as mere “cases”. Such contradictions – which reveal difficulties in managing the empirical component of theories – have also been mentioned by Dagher et al (2004). Both cases – whether learners consider theories as necessarily confirmed or as mere hypotheses – lead to further difficulties: if students claim that the theory must necessarily be confirmed, they leave little room for further prediction through theories. This finding correlates with corresponding investigations (Meyling 1997, Dagher et al 2004).
Through discussion and a breakdown of Maxwell’s texts, students distinguish the fact that “light is an electromagnetic wave” was a prediction of Maxwell‘s e/m theory which resulted from a combination of observations and mathematical thinking. Experimental confirmation of this fact was achieved several years later. Thus, the students gradually attribute the characteristic of prediction to theory.
Once the students had overcome their previous difficulties, they were able to gradually develop the relationship between laws and theories and express the view that theories explain laws – relating to the difficulty of distinguishing between description and explanation, theories may correct or add to a law – relating to the difficulty of laying down the limits on law’s implementation , and theories may establish new laws – relating to students’ difficulties with the experimental proof of theories.
Finally, students had difficulty understanding models’ other functions beyond representation. This is highlighted by Grosslight et al (1991), Meyling (1997), Treagust et al (2002). Maxwell’s modeling processes gradually made students conclude in their descriptions of models that models play an active role in the construction of theories as well as playing a representational role; they contribute to the process of theory development, since scientists’ thinking is facilitated by modeling.
The following findings also emerged. Many students gave answers that reveal epistemological contradictions. For example, they may answer that laws are more confident than theories because they are “proven” while theories aren’t and then go on to argue that scientific theories are scientifically “proven” proposals. It seems that they cannot decide on the role of empirical data in the description of laws and theories. Corresponding findings emerged from the research of Koulaidis & Ogborn (1995).
Most students do not distinguish the notions of “proof” and the experimental verification. Thus, while proof is a mathematical term denoting a logical conclusion, experimental verification is some kind of strong evidence that a theory or law applies. However, the possibility that the theory can be disproved by subsequent experiments still exists. The fact that students used the terms confirmation and proof interchangeably is revealing of the difficulties they have handling the distinction between them. This was also observed by Dagher et al (2004), which suggested an explicit distinction between the terms.
The study indicates that there is still a good deal that needs to be investigated in depth with regard to NoS in primary and secondary education but also tertiary education. The implementation of classroom research is highly recommended. Following level adaptation and updating based on the findings of the present research, such research could provide further evidence for effective teaching NoS elements in a broader educational context.
However, since the field of investigation was quite extended in terms of subjects under consideration, it is suggested that future research focus on specific issues, particularly:1. The concept of law in different science subjects (i.e. Physics, Chemistry, Biology). For example Faraday’s law, has different characteristics from Mendel’s law in Biology. The exploration of these differences would highlight similarities and differences of science subjects. 2. Exploring multiple significations of certain terms used in science and in everyday life. Words such as ‘law’, ‘theory’, ‘explanation’, ‘hypothesis’ etc., seem to affect and often interfere with students’ ability to understand scientific concepts. The understanding of these terms is perhaps a prerequisite to understand the content science.3. Exploring the triptych laws, theories and models as a framework of understanding other aspects of the NoS; i.e. the fact that science is based on experimental data, the difference between indication and inference, or the socio-cultural context of science. As one student put it: “The truth is that, in the end, I understood that science is a team sport which isn’t necessarily only played in a laboratory conducting experiments. There are other factors that influence the production of scientific knowledge … It may not be a coincidence that Faraday was poor and mathematically illiterate, while Maxwell was wealthy. “4. Exploring NoS as a framework for understanding science itself. Understanding concepts such as the difference and the relationship between the notions of theory and law helps to create the proper conditions for particular laws and theories to become more comprehensible. As one student said: “If you do not know the whole, i.e. what is a scientific law in general, how are you supposed to learn the parts? For example Faraday’s law? “.5. Finally, the study indicates a need for further research into the correlation between students’ attitudes towards science with the history of science. In one student’s words: “Who would expect that we would enjoy working with Maxwell? … Personally, now that I‘ve started to understand, I will stay involved with science and its history, it’s amazing!”
Key words: History and Philosophy of Natural Sciences, Nature of Science, Laws, Theories, Models, Maxwell’s Electromagnetic Theory, Teaching Experiment, Learning Sequences.
Literature:
Blanco, R. & Niaz, M. (1997). Epistemological Beliefs on Students and Teachers about the Nature of Science: from “baconian inductive ascent” to the “irrelevance” of scientific laws. Instructional Science, 25, 203-231.
Akerson, V. & Hanuscin, D. (2007). Teaching Nature of Science through Inquiry: Results of a three years Professional Development Program. Journal of Research in Science Teaching, 44 (5), 653-680.
Dagher, Z., Brickhouse, N., Shipman, H. & Letts, W. (2004). How some college students represent their understandings of the nature of scientific theories? International Journal of Science Education, 26 (6), 735-755.
Grosslight, L., Unger, Chr., Jay, E. & Smith, C. (1991). Understanding Models and their Use in Science: Conceptions of Middle and High School Students and Experts. Journal of Research in Science Teaching, 28 (9), 799-822.
Irez, S. (2006). Are we prepared? An Assessment of Preservice Science Teacher Educators’ Beliefs about Nature of Science. Science Teacher Education, 90, 1113-1143.
Koulaidis, V. & Ogborn, J. (1995). Science Teachers’ philosophical assumptions: how well do we understand them? International Journal of Science Education. 17 (3), 273-283.
Mackay, L. (1971). Development of Understanding about the Nature of Science. Journal of Research in Science Teaching, 8 (1), 57-66.
Meyling, H. (1997). How to change students’ conceptions of the epistemology of science. Science & Education, 6, 397–416.
Rubba, P. & Andersen, H. (1978). Development of an Instrument to Assess Secondary School Students’ Understanding of the Nature of Scientific Knowledge. Science Education, 62 (4), 449-458.
Treagust, D., Chittleborough, G. & Mamiala, Th. (2002): Students’ understanding of the role of scientific models in learning science. International Journal of Science Education, 24 (4), 357-368.
Thesis full reference:
Stefanidou C., (2013). The Role of History and Philosophy of Natural Sciences in Natural Science Teaching: Teaching and Learning about the Nature of Science – Laws, Models and Theories – through the History of Electricity. Unpublished Ph.D thesis. Department of Physics, Department of Primary Education, National and Kapodistrian University of Athens, Athens, Greece.
The major concepts and findings from the thesis are published – among others – in the following journal articles and chapters
Stefanidou C., Stavrou D. & Skordoulis C. (2013) “Teaching and Learning the Heuristic Role of Models in Theory Construction in the Context of Nature of Science: The case of Maxwell’s vortex idle wheel Model”, Enabling Scientific Understanding through Historical Instruments and Experiments in Formal and Non-Formal Learning Environments, Heering P., Klassen S., Metz D. (Eds.), Flensburg University Press, pp. 111-126.
Skordoulis C. & Stefanidou C. (2011). “Epistemological Aspects of the Historiography of Science in Greece”, Organon, 43, 29-47.
Skordoulis C. & Stefanidou C. (2014). “Subjectivity and Objectivity in Science: An Educational Approach”, Advances in Historical Studies, 3, 183-193. doi: 10.4236/ahs.2014.34016.
Correspondence
https://uoa.academia.edu/ConstantinaStefanidou
Tel: 0030 6977 322772
