PHYSICAL SCIENCE 2ND SEM

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Rodneymalaluan

Cards (22)

  • Astronomoy - studies of celestial object for ex. Sun, Earth, and Solar System
  • 500 B.C - during this period the greeks already believed that the Earth's shape was round, not flat .
  • Pythagoras - first proposed the spherical earth
  • Oblate Spheroid - the Earth shape(bulging at the equator and squeezed poles)
  • Anaxagoras - (500 to 430 B.C) supported the idea of Pythagoras and he observed that the shadow earth cast on the moon during a lunar eclipse was circular
  • Erastothenes - measured the Earth's circumference with a stick, a knowlegde of the distance from alexandria to syene, and geometric principle
  • Alexandria - Shadow
  • Syene - No Shadow
  • 7.2 degrees - it was the angle of the shadow casted by a stick at noon on the sunmer solstice in alexandria and it was 1/50 of a complete circle
  • 5000 stadia - it is the distance of alexandria to syene
  • 250,000 - the measure of earth circumference
  • Anaxagoras - explained the causes of the phases of the moon
  • Anaxagoras - believe that the moon shone by reflected sunlight. since it's sphere, only half illuminated part that visible from the earth changed periodically.
  • Aristotle - (around 340 B.C) included the following in his argument supporting a spherical earth.
  • Polaris - Position of the North star
  • Aristotle supported the idea of
    •Position of the North star (Polaris, Thuban, Vega)
    •The shape of the moon and the sun
    •Ships disappearing over the horizon
  • Eudoxos - proposed the system of fixed spheres. Also, he belived that the sun, the moon, and the 5 known planets were attched to these spheres which carried heavenly bodies while they revolved around the stationary earth.
  • Claudius Ptolemy - developed the geocentric model of the solar system. He believed that all celestial objects moved on circular orbits centered at the Earth.
  • Hipparchus - observed and compared the brightness of 850 stars and arranged them into order of brightness of magnitude
  • Aristarchus - proposed that the sun was the center of the universe (Heliocentric)
  • Sundial - earliest time keeping device (gnomon)
  • Rising and setting of the sun - babylonian and egyptians used a gnomon in systematically obeserving the motion of the star