The Earth

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The Earths Moon
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Motions of Earths Moon

• Revolution of the moon around Earth affects
  phases of the moon, tides and eclipses
• The moons orbit is tilted at 5 degrees
• The moons period of revolution is 27.5 days
• The moon rotates at the same speed that it
  revolves, so the same side of the moon is always
  facing Earth

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Phases

• The moon rises 50 minutes later each day
• Half of the moon is always lit (except during a
  lunar eclipse) due to the light from the sun
• Depending on where the moon is in its orbit,
  observers on Earth see varying amounts of the
  lighted half

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WHEN IN DOUBT, CHECK IT OUT! ESRT page 15
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Phases of the Moon
Moon Phase Time in days for one phase cycle Tides (spring or neap) Eclipse Possible?
1. New 0 Spring Yes, Lunar
2. New crescent 3.75 No
3. First quarter (half) 7.5 Neap No
4. New gibbous 11.25 No
5. Full 14.5 Spring Yes, Solar
6. Old gibbous 18.5 No
7. Third quarter (half) 22.5 Neap No
8. Old cresent 26 No
1. New 29.5 Spring Yes, Lunar
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• It takes 1 week to go from new to 1st quarter, 1
  week to go from 1st quarter to full (or 2 weeks
  total), etc
• It takes 29.5 days for the moon to go from the
  new moon phase, through all of the other phases,
  back to the new moon phase-
• It is 2 days longer than period of revolution
  because as the moon orbits Earth, Earth is moving
  by orbiting the sun

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Vids

• Moon Phases
• Phases again
• Falling Moon
• How the Moon Formed

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Tides
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• Tides The cyclic rise and fall of ocean waters
  due to the gravitation between the Earth, the
  moon and the sun

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Spring Tides / Neap Tides

• Spring Tides When the highest high tides and the
  lowest low tides occur, which happens near the
  full and new moon phases
• This is due to the sun and the moon pulling in
  the same line
• Neap Tides Least amount of change between high
  tide and low tide- occurs during the first and
  last quarter phases of the moon

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• The sun is larger, but the moon is closer, so the
  moon has a much greater effect on the tides

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Based on the diagram, which types of tides have
a larger range?
SPRING TIDES
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There are not exactly 12 hours between high
tides because the moon revolves around the
Earth while the Earth rotates