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Asia-Pacific Forum on Science Learning and Teaching, Volume
7, Issue 2, Article 1 (Dec., 2006) Shu-Chiu LIU Historical models and science instruction: A cross-cultural analysis based on students’ views
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The Greek “sphere making”
One of the key elements of the history of Western astronomy, as Albanese et al. (1997) summarized, is the construction of an Earth model and its place in the universe; as a whole, the Earth had been a central object for the early scientists.
The general picture of the universe for most Greek astronomers and philosophers from the fourth century on was the Earth being a tiny sphere suspended without movement at the center of a much bigger rotating sphere which carried the stars. The Sun moved in the ample space between these two spheres. There was absolutely nothing outside of the outer sphere. This was the ancient version of the cosmological model which developed through time into the medieval and modern world. This two-sphere framework worked very well in the Greek astronomy, for it sufficiently explained the observations of the heavens (Kuhn ,1985). Eudoxo of Cnido (408-355 B.C.), for example, proposed a cosmological model with concentric spheres centered at a fixed and static Earth, using 27 spheres to account for all the motions of heavenly bodies known to the time. This was later improved by Aristotle (4th Century B.C.) in order to explain the brightness of the planets; the spheres became 55 in number. Aristotle’s “onion” universe was again revised by Ptolemy (87-150 A.D.), who added in more artifacts known as epicycles, and was turned into the “wheels-within-wheels” universe (Koestler, 1959).
Copyright (C) 2006 HKIEd APFSLT. Volume 7, Issue 2, Article 1 (Dec., 2006). All Rights Reserved.