Ancient Greek physics and astronomy.pptx

SCIENCE S A COLLECTION OF KNOWN TRUTH ABOUT UTHE NIVERSE THAT DEVELOPS AND EXPANDS OVER TIME

1. Ancient Greek physics and astronomy

2. objectives 1. Summarize(K) ancient Greek on the three types of terrestrial motion and the perfection of celestial motion. [IVa-36] 2. Enumerate(K) naked-eye astronomical proofs that the Earth is round or spherical. [IVa-38]

3. science as “a collection of known truths about the Universe that develops and expands over time.” science is dynamic and ever changing. science develops when better models are found, clearer and more useful mechanisms are used to explain a group of phenomena, more accurate and precise details are observed, and many more

4. astronomy is a major influence to the development of Physics. ancient Greek philosophy, cosmology and astronomy. The Greeks divided the universe into domains, the celestial domain and the terrestrial domain.

5. Diurnal motion of the sky — the appearance that the objects in the sky moves relative to the Earth’s local horizon (celestial objects: moon, Sun, stars, planets; there were only five known planets: Mercury, Venus, Mars, Jupiter, Saturn) as observed for one whole day at the same location on Earth.(rotation)

6. Annual motion of the sky — the appearance that objects in the sky moves relative to the background stars as observed at the same time of the day and at the same location on Earth.(revolution)

7. Ancient Greek Philosophers Pythagoras Socrates Plato Aristotle

8. Pythagoras (c. 570 - c. 495 BC) — Universe is mathematical; mathematics as the best way to express truth about the Universe; Sun, moon and Earth are spherical; placed Earth as the center of the Universe. [3,7]

9. Plato (c. 427 - c. 347 BC) — attainment of perfection as absence of change; mathematical symmetries to demonstrate perfect shapes (sphere and circle); celestial spheres being crystalline and contains the moon, the Sun and the stars; explaining the shadows — read on Plato’s Allegory of the Cave and the Allegory of the Divided Line — as his description or framework on how to look at the Universe, in particular that the daily and annual patterns of the sky must have a greater reality besides its appearance. [2]

10. Eudoxus (of Cnidus, 408 - 355 BC) — followed previous models of the universe but added auxiliary spheres to provide appropriate tilt to the planets’ path [7]

11. Aristotle (384 - 322 BC) — two-domain system with terrestrial domain containing four elements that tries to attain perfection by being in their natural location relative to the center of the Universe: the center of the Earth. He was a learner of Plato. He taught that the moon sun, five planets and the stars all revolved around the earth. (384-322 B.C) concluded that the earth is spherical because of          the curved shadow it casts on the moon during eclipses

12. Two-domain view of the Universe The Celestial domain is perfect hence can only be made up of the perfect substance they called “ ether” and can only move in perfect motion : circular in path and constant in speed. The terrestrial domain objects are imperfect and that the tendency of things to attain perfection is the cause of their motion. Meanwhile, they also believed that things, depending on their composition of the elements — fire, air, water, and earth — tend to move towards the center of the Universe (center of the Earth) or away from it with earth, naturally, as at the center. Fire and water naturally move away from the center.

13. Domain Elements Motion Terrestrial domain fire
 air
 water
 earth alteration
 natural motion
 violent motion Celestial domain ether perfect motion: circular and constant speed

14. evaluation Why A ristotle concluded that the earth is spherical ? Why celestial domain said to be perfect motion? Why terrestrial domain said to be imperfect motion?

15. Answer key 1. Aristotle (384-322 B.C) concluded that the earth is spherical because of          the curved shadow it casts on the moon during eclipses . 2.Celestial domain is perfect hence can only be made up of the perfect substance they called “ ether” and can only move in perfect motion : circular in path and constant in speed . 3.terrestrial domain objects are imperfect and that the tendency of things to attain perfection is the cause of their motion(alteration, natural motion and violent motion)

16. assignment Explain the three models of the universe a.Ptolemic b.Copernican c. Tychonic