1 hrly gs ch 02 earth movement

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1 hrly gs ch 02 earth movement

  1. 1. Earth Movement
  2. 2. Axis of Earth • What is Axis? Earth's axis is the imaginary line which goes through the north and south poles and around which Earth spins.
  3. 3. • Think of Earth as a Giant Spin top
  4. 4. Tilted Axis • Earth axis is Tilted/Inclined at an angle of 66.5 degrees to the plane of its orbit. Angle from Plane is 66.5 Degree
  5. 5. Earth’s Hemispheres
  6. 6. NORTHERN HEMISPHERE SOUTHERN HEMISPHERE
  7. 7. EARTH MOVEMENT • Earth is in a constant motion and performs two different movements: • Rotation around it’s Axis. • Revolution around Sun
  8. 8. Rotation of Earth • Causes Day & Night • It takes approx. 24 Hours for earth to complete one rotation around it’s Axis. • The side of Earth facing Sun has Day while the side away has Night.
  9. 9. • Earth rotation is anti-clockwise • Because of which: - Sunrises in the east - Sun travels across the sky - Sunsets in the west
  10. 10. Effects of Tilt • Difference in the Length of Day & Night. • Different Seasons at same time.
  11. 11. Revolution of Earth • Revolution is the movement of one object around another object. • Earth is revolving around Sun and completes one Revolution In 365 Days and 6 Hours
  12. 12. • Solar year = 365 and ¼ days • Calendar = 365 days • Difference = ¼ days or 6 hours in a year ¼ + ¼ + ¼ + ¼ = 1 day
  13. 13. Leap Year • To compensate for every extra 6 Hours, a day is added to the calendar after every four years as 29th February: Leap Year = Last two Figure of Desired Year 4 • If answer has no remainder it is a leap year.
  14. 14. Leap Year or not? • 1934 Not a leap year • 1956 Leap year • 1978 Not a leap year • 1994 Not a leap year
  15. 15. Seasons • This revolution of Earth is constant along with the Axial Tilt which gives us different seasons • As Earth revolves, at different places the seasons occur.
  16. 16. Spring Equinox Winter Solstice Summer Solstice Autumnal Equinox
  17. 17. Summer Solstice Winter Solstice
  18. 18. • At Equinox March 21st & September 23rd all places have equal Day and Night.
  19. 19. Moon
  20. 20. High / Low Tides • As Earth & Moon attract each other toward themselves like two magnets. • The moon tries to pull at anything on the Earth to bring it closer. • But, the Earth is able to hold onto everything except the water. Because it is constantly moving and that allows moon to attract it
  21. 21. • This gravitation results in high and low tides each day. And Ocean moves from high tide to low tide and vice versa.
  22. 22. • As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall.
  23. 23. Eclipse • Definition – An obscuring of the light from one celestial body by the passage of another between it
  24. 24. • There are two kinds of Eclipse but both occur as a result of relative positions of earth moon and sun - Solar Eclipse - Lunar Eclipse
  25. 25. Solar Eclipse • When Moon comes between Sun & Earth.
  26. 26. • An eclipse of the sun occurs when the moon revolving in its orbit around the earth comes between the sun and the earth. The moon blocks the light of the sun and a shadow of the moon is cast over the earth's surface.
  27. 27. Types of Solar Eclipse • There are two types of solar eclipse: – Total solar eclipse – Annular solar eclipse – Partial solar eclipse
  28. 28. • Total Solar Eclipse – When the moon completely obscures the sun • Annular Solar Eclipse – When the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring surrounding the outline of the Moon • Partial Solar Eclipse – When the Sun and Moon are not exactly in line and the Moon only partially obscures the Sun
  29. 29. Solar Eclipses in 2012 Type Date Region Annular May 20 China, Japan, Pacific, West U.S. Total Nov 13 North Australia, South Pacific
  30. 30. Lunar Eclipse • When Earth comes between Sun and Moon
  31. 31. • A lunar eclipse is when the Earth comes between the Sun and the Moon causing a shadow of Earth on the Moon.
  32. 32. Can be viewed with naked eye
  33. 33. Types of Lunar Eclipse • There are two types of solar eclipse: – Total lunar eclipse – Partial lunar eclipse
  34. 34. • Total Lunar Eclipse – When the Moon travels completely into the Earth’s umbra • Partial Lunar Eclipse – When only a portion of the Moon enters the umbra
  35. 35. Lunar Eclipses in 2012 Type Partial Date Jun 04 Region Asia, Aus., Pacific, Americas

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