Free Executive Summary - Elmhurst College
Free Executive Summary - Elmhurst College
Free Executive Summary - Elmhurst College
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Learning to Think Spatially: GIS as a Support System in the K-12 Curriculum<br />
http://www.nap.edu/catalog/11019.html<br />
SPATIAL THINKING IN EVERYDAY LIFE, AT WORK, AND IN SCIENCE 61<br />
FIGURE 3.4 Epicycles in the Ptolemaic system. SOURCE: http://abyss.uoregon.edu/~js/glossary/<br />
ptolemy.html. Reproduced by permission from Dr. Jose Wudka.<br />
FIGURE 3.5 Retrograde motion. In modern heliocentric theory, the relative motions of the planets around<br />
the Sun causes the outer planets, those further away from the Sun than Earth, to appear to move backwards<br />
relative to the fixed stars on a regular basis. Note also that the inner planets are never seen at a large angular<br />
separation from the Sun. These two features were well known even to prehistoric observers, and any explanation<br />
of the structure of the solar system had to explain these motions. SOURCE: Abell, 1969.<br />
Copyright © National Academy of Sciences. All rights reserved.