Successfully reported this slideshow.

8th Grade Chapter 2 Lesson 3


Published on

For Student Use Only

Published in: Education, Technology
  • Be the first to comment

  • Be the first to like this

8th Grade Chapter 2 Lesson 3

  1. 1. 8 th Grade Chapter 2 Lesson 3 Pgs. 75-78 For Student Use Only
  2. 2. Astronomy <ul><li>Astronomy first began as a way to tell time. </li></ul><ul><ul><li>Many people based their months, years, and holidays on the apparent movement of celestial bodies. </li></ul></ul><ul><ul><ul><li>Most of our units of time are based on the motions of the heavens. </li></ul></ul></ul>
  3. 3. Astronomy <ul><li>The Celestial Sphere: </li></ul><ul><ul><li>Celestial Sphere: the apparent dome to which the stars appear to be attached </li></ul></ul><ul><ul><ul><li>We see only half of the sphere at a time. </li></ul></ul></ul>
  4. 4. Astronomy <ul><li>Celestial Sphere: </li></ul><ul><ul><li>______________: separates the visible part of the sphere with the part we cannot see </li></ul></ul><ul><ul><li>______________: point above an observer on the celestial sphere directly above the observer </li></ul></ul><ul><ul><li>______________: point directly below the observer </li></ul></ul>
  5. 5. Astronomy <ul><li>Celestial Sphere: </li></ul><ul><ul><li>Heavens rotate from East to West once a day around the poles </li></ul></ul><ul><ul><ul><li>North Celestial Pole: point above the North Pole </li></ul></ul></ul><ul><ul><ul><li>South Celestial Pole: point below the South Pole </li></ul></ul></ul>
  6. 6. Astronomy <ul><li>Celestial Sphere: </li></ul><ul><ul><li>Celestial Equator: (equinotial) encircles the heavens midway between the celestial poles </li></ul></ul><ul><ul><ul><li>This is tilted from the celestial equator is tilted from the horizon </li></ul></ul></ul>
  7. 7. Astronomy <ul><li>Time: </li></ul><ul><ul><li>Day: length of day is decided by heavenly bodies and Earth’s rotation </li></ul></ul><ul><ul><ul><li>Meridian: imaginary line can be used to measure the motion of celestial objects </li></ul></ul></ul>
  8. 8. Astronomy <ul><ul><li>Time </li></ul></ul><ul><ul><ul><li>Sidereal Time: one rotation of the earth relative to the stars </li></ul></ul></ul><ul><ul><ul><li>Apparent Solar Time: measured from noon to noon it equals the amount of time the sun it takes to cross the meridian twice </li></ul></ul></ul>
  9. 9. Astronomy <ul><ul><li>Time </li></ul></ul><ul><ul><ul><li>Mean Solar Time: average (or mean) time of the solar day </li></ul></ul></ul><ul><ul><ul><li>Equation of time: the difference between mean solar time and apparent solar time </li></ul></ul></ul><ul><ul><ul><li>Standard Solar Time: Time zones around the world </li></ul></ul></ul>
  10. 10. Astronomy <ul><li>Summer’s Standard: </li></ul><ul><ul><li>This is due to the extra sunlight (time is adjusted forward an hour) </li></ul></ul><ul><li>Time: </li></ul><ul><ul><li>24 hour day </li></ul></ul><ul><ul><ul><li>Divided into 12 hour AM (ante Meridien) </li></ul></ul></ul><ul><ul><ul><li>12 hour PM (post Meridien) </li></ul></ul></ul>
  11. 11. Astronomy <ul><li>Time: </li></ul><ul><ul><li>The military and other countries operate on the 00-23 hundred hours. </li></ul></ul>