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Asia-Pacific
Forum on Science Learning and Teaching, Volume 6, Issue 2, Article
1
(Dec., 2005) Shu-Chiu LIU From geocentric to heliocentric model of the universe, and the alternative perspectives
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Asia-Pacific
Forum on Science Learning and Teaching, Volume 6, Issue 2, Article
1
(Dec., 2005) Shu-Chiu LIU From geocentric to heliocentric model of the universe, and the alternative perspectives
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Changing the Perspective from "On the Surface of the Earth" to "Beyond"
1. Models of the universe
Students' elicited models of the universe fall into two groups: earth-centred and sun-centred views. The analogous models can be found in history, as the geocentric and heliocentric models characterized the astronomical development in Europe. At this point, historical models find their positions in instruction - as a means of intermediate models in the learning process from the student's alternative conceptions to the intended scientific model. The students can project their conceptions onto these views in history. As the essential difference between the geocentric and heliocentric views is the perspective taken on the surface of earth and beyond, it should be therefore a high point for instruction to use the historical models. To be more precise, the geocentrism and heliocentrism of historical models can be introduced to students in relation to the understanding of the perspective on the surface of the earth and beyond.
As a matter of fact, scientific progress often involves a change in the perspective man takes. For the learner, the change of perspective is significant, too, in the process of conceptual development. The transition from a geocentric to a heliocentric view is typically a change in man's perspective; the former is constrained by the experience and observation based on the surface of the earth, whereas the heliocentric view was regarded as the first step that man goes beyond the surface of the earth to view the universe. This is indeed the point upon which we should lay stress while using the historical models. Students do have similar difficulty to take a different perspective beyond where they are located. When they are able to move from the perspective on the earth to that beyond the earth, they are on the way towards understanding the intended scientific knowledge in instruction, and, moreover, of the nature of science.
2. Models of the earth
Students' difficulty in relating the flat earth as viewed on the surface of the earth to the spherical earth as explained by other people is also derived from the perspective students take from where they locate. To understand the sphericity of the earth, the student must first realize there is a difference between what is seen on the surface of the earth, while the observer is a tiny point as opposed to the whole earth, and outside the earth, while the earth can be fully captured in the view. The historical models of the earth can be therefore placed in the students' learning process for understanding the perspective beyond the earth. For example, the historical intuitive ideas about the shape of the earth, such as Homer's shield-like earth, Anaximander's cylindrical earth, and the disk- or plate-like earth held by early Chinese scientists for centuries, are those that can be understood as the perspective taken on the earth surface. In contrast, a spherical model of the earth was established in the Greek antiquity as early as in the six century B.C. The arguments scientists put forward to this model can be illustrated in the teaching the sphericity of the earth in relation to the perspective beyond the earth.
Furthermore, the contrasting development of this subject in Europe and China before the 17th century, if introduced carefully, can convey that, first, people at different parts of the world actually held different "truths", and, second, ideas are bound to the cultural context. Students could reflect on their own thoughts in the light of the historical examples.
Copyright (C) 2005 HKIEd APFSLT. Volume 6, Issue 2, Article 1 (Dec., 2005). All Rights Reserved.
