Phases,

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Phases, Eclipses

• Chapter 1 Earth, Moon, Sun

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Motions of the Moon
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Why is the day on the moon the same length as a
year on the moon?

• Rotation Day Revolution year
• Since it takes 27.3 Earth days for the moon to
  rotate (day) and 27.3 Earth days for the moon to
  revolve (year), the day and a year are the same
  length

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Checkpoint How many days does it take the moon
to revolve once around Earth?

• It takes the moon 27.3 Earth days to revolve
  around Earth.
• It also takes the moon 27.3 Earth days to rotate

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Phases of the Moon
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The different shapes of the moon you see from
Earth are called _____.

• phases

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The moon goes through its whole set of phases
each time it _____ around Earth, or about once a
_____.

• revolves
• month

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Guide For ReadingWhat causes the phases of the
moon?

• The phases of the moon are caused by the change
  of the relative positions of Earth, the moon, and
  sun.
• Since the moon revolves around Earth we see it
  from different angles
• The ½ of the moon that faces Earth is not always
  the ½ lit up by the sun causing the moons shape
  to appear to change
• The phase of the moon you see depends on how much
  of the sunlit side of the moon faces Earth

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What is the length of time from a new moon to the
next new moon?

• 29.5 Earth days
• Since Earth is revolving it takes an extra 2.2
  Earth days for the sun, moon and Earth to line
  up, causing the next new moon

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Checkpoint Since the moon does not produce
light, how can you see it?

• Light from the sun reflects off the moon,
  enabling it to be seen from Earth.

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Eclipses
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Figure 6 Interpreting DiagramsHow large is the
angle between Earths orbit and the moon s
orbit?

• The angle between Earths orbit and the of the
  moon is 5º

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When does an eclipse occur?

• In a rare occasion when the moon or Earth becomes
  directly between the sun and the other and cast a
  shadow on that object

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The two types of eclipses are ______ ______.

• lunar
• solar

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Solar Eclipses
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Solar Eclipse

• A solar eclipse occurs when the moon comes
  directly between the sun and Earth
• The moon blocks Earth from sunlight and cast a
  shadow
• Earths sky becomes darker and you can only see
  the corona of the sun

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At what phase of the moon could a solar eclipse
occur?

• A new moon when the moon becomes directly between
  the sun and Earth

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The darkest part of the moons shadow is called
the _________.

• Umbra

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Why are the people in the umbra the only ones
that experience a total solar eclipse?

• The umbra is the darkest part of the of the
  moons shadow
• People who are in the umbra are in the darkest
  part of the shadow where the moon is almost
  completely blocking sunlight from reaching Earth,
  except for the suns corona

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Penumbra

• The larger less dark shadow cast by the moon
  during a solar eclipse and by Earth during a
  lunar eclipse

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Lunar Eclipses
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What is a lunar eclipse?

• A lunar eclipse occurs when Earth comes directly
  between the sun and moon
• Earth blocks the moon from sunlight and cast a
  shadow
• The moon turns a red/orange color

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Figure 8 Interpreting Diagrams What is the
difference between Earths umbra and penumbra?

• The umbra is in the area of total darkness, the
  penumbra is the area of partial darkness

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Checkpoint Why do lunar eclipses occur only at
full moon?

• Earth must come between the sun and the moon
  during a lunar eclipse this only happens during
  the full moon phase.

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Guide For Reading What causes solar and lunar
eclipses?

• When the moons shadow hits Earth or Earths
  shadow hits the moon, an eclipse occurs.
• Eclipses occur when the moons orbit which is
  usually tilted becomes not tilted and the sun,
  moon and Earth line up perfectly