Aristotle's Natural Movement

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Natural Movement a. Natural movement refers to the system around Aristotle’s belief in the five elements: earth, water, air, fire, and ether. Ether is the element of the heavens and was used to explain the movement of celestial bodies, while the remaining four are elements of the Earth, and thus were used to explain movement on Earth. Aristotle created a ringed diagram, like a cross-section of an onion, to explain this natural movement. He placed the element earth in the center of the diagram as he viewed Earth to be the center of the universe. Next came water, then air and fire rounded out the last of the Earthly elements. He organized them in this manner because of a series of observations he made, when Aristotle threw some dirt it returned…show more content…
Using this natural movement idea Aristotle was able to explain what elements an object was made of by the way the object moved, for example, a book if dropped would fall to the ground, meaning that it must be composed of the earth element. For his explanation into how celestial bodies or the heavens moved he used the element ether, which was considered to be the perfect element and was believed to make up planets, making them by extension perfect structures. In the minds of Ancient Greek’s perfect structures could only move in a perfect way, or a perfect circle. The significance of natural movement was that it allowed Ancient philosophers to be able to explain the movement of not only natural substances on Earth but also to explain the movement of the heavens…show more content…
Equant refers to ancient Greco-Roman astronomer Ptolemy’s geometric model of what he believed to be the shape of the universe. Greek astronomers believed that because the heavens, or celestial bodies, were created perfect they must move in perfect form and in this case perfect circles. However, there were contradictory observations made that did not support this perfect form idea such as planets changing speed or retrograde motion. In order to address these issues but still maintain the original perfect form theory, Ptolemy offered the idea that the “equant” model which would serve to explain how the inconsistencies in the planetary motion were still in accordance with the old Greek theory. The equant was a mathematical point not in the center of the orbital, which a planetary body moved around. As was not in the center of the planets orbital, as the planet rotated it would change the speed the closer to or farther away the planet was from the central point. In addition to changing the central point, Ptolemy also added a secondary orbital to each planet in order to explain retrograde motion, where the planet appeared to be going backward. By adding this second orbital Ptolemy could explain how the planet was rotating in two separate orbitals but still followed the perfect circle. The significance of the equant model was that it was a farther explanation on the old ideas of Astronomy that supported the base perfect form theory but also was able to explain how once

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