Phases, Eclipses, and Tides

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Phases, Eclipses, and Tides

• Chap 15 Sec 3

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Essential Questions Chap15 Sec 3

1. What causes the phases of the moon?
2. What are solar and lunar eclipses?
3. What causes the tides?

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Motions of the Moon

• The moon rotates on its axis and revolves around
  Earth.
• The changing relative positions of the Earth,
  sun, and moon cause the moon to appear to change
  shapes we see the different phases of the moon.

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• The moon revolves around Earth. It takes the moon
  about 27.3 days to revolve around Earth.
• The moon rotates on its axis in about the same
  time that it revolves around Earth. For this
  reason, we only see one side of the moon.
• A year and a day on the moon would be the same!!
• As the moon and Earth move, their positions
  change in relation to each other. Their positions
  also change in relation to the sun.

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Full Moon
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• The changing relative positions of the moon,
  Earth, and sun cause the phases of the moon,
  eclipses, and tides.

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Phases of the Moon

• The moon does not give off its own light. The
  moon reflects light from the sun.
• The moon appears to have different shapes at
  different times. These different shapes of the
  moon that you see are called phases.
• As the moon revolves around Earth, you see the
  moon from different angles. You cannot always see
  all of the part of the moon that is lit by the
  sun.

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• The phase of the moon you see depends on how much
  of the sunlit side of the moon faces Earth.
• It takes 29.5 days for the moon to go through all
  phases.

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The Dark Side of the Moon

• We often think of the dark side of the moon as
  the side that faces away from Earth.
• This isnt always true only at a certain phase
  of the moon!
• At some point during 29.5 days, every part of the
  moon will be dark.

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Full Moon
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First Quarter Moon
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Waning Crescent Moon
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Phases of the Moon
Teacher explain this diagram.
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Essential Question Answered

• What causes the phases of the moon?
• The changing positions of the moon, Earth, and
  sun causes the phases of the moon.
• Stop here complete foldable notes.

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Eclipses

• An eclipse (ih KLIPS) is when an object in space
  comes between the sun and another object. For
  example, an eclipse occurs when the moon comes
  between the sun and Earth.

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• When the moons shadow hits Earth or Earths
  shadow hits the moon, an eclipse occurs.
• Latin words for sun and moon are solar and lunar.

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Solar Eclipse

• Solar eclipses occur when the moon moves in a
  line directly between Earth and the sun, casting
  a shadow on Earth.
• A solar eclipse happens only during a new moon.

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Solar Eclipse
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Total Solar Eclipse

• The umbra (darkest part of the moons shadow),
  falls on a small area of Earth.
• The sky will become totally dark you can even
  see the stars and the suns corona (outer
  atmosphere of the sun).
• The area in the umbra sees a total solar eclipse.
  It is a very small place on Earth.
• The next total solar eclipse is on July 22, 2009
  and youll have to travel to India, China, or
  parts of Japan to see it!!

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Partial Solar Eclipse

• People in the penumbra, or lighter shadow of the
  moon, see a partial eclipse.
• The sun is partially blocked out.
• This shadow covers a larger area of Earth.
• The next partial solar eclipse is Jan. 26, 2009
  but youll have to go to India!

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Lunar Eclipse

• Lunar eclipses occur when the moon passes through
  Earths shadow.
• A lunar eclipse occurs when there is a full moon.
• During a lunar eclipse, Earth blocks sunlight
  from reaching the moon.

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A Lunar Eclipse
These pictures show the moon passing into Earths
shadow, being covered completely by the shadow,
then moving out of the shadow. The red
appearance is because Earths atmosphere bends
some sunlight around Earth onto the moon.
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Total Lunar Eclipse

• The moon moves through Earths umbra (darkest
  part of the Earths shadow).
• You can see the edge of Earths shadow on the
  moon before and after a total lunar eclipse.
• Lunar eclipses are visible to everyone that can
  see the moon right then (the dark side of Earth).
• The next total lunar eclipse will be on Feb. 21,
  2010 and we should be able to see it!

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Partial Lunar Eclipse

• Most lunar eclipses are partial.
• They occur when the moon passes through a part of
  the Earths umbra.
• The next partial lunar eclipse is on Feb. 9, 2009
  but will not be visible to us. Fly out west or
  to Asia to see it.
• Two other partial lunar eclipse will occur on
  July 7 and August 6, 2009 and both should be
  visible to us.

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Lunar Eclipse
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Student Photos of the Feb. 20, 2008 Total Lunar
Eclipse
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(No Transcript)
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Essential Question - Answered

• 2. What are solar and lunar eclipses?
• Solar eclipses happen when the moons shadow
  falls on Earth and from our view, the sun is
  covered by the moon. Lunar eclipses happen when
  the moon moves into the Earths shadow and the
  sunlight is temporarily blocked from the moon.
• Stop and complete foldable and notes.

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Tides

• Tides are the regular rise and fall of ocean
  water.
• The moons gravity causes tides. The force of the
  moons gravity causes ocean water on Earth to
  move higher in some places and lower in other
  places.
• The suns gravity also pulls on Earths ocean
  waters.

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Spring Neap Tides

• During a new moon, the sun, moon, and Earth are
  lined up in a straight line. The combined forces
  of the sun and the moon cause spring tides. A
  spring tide is the highest possible high tide.
• Sometimes, the sun, moon, and Earth form a right
  angle. This arrangement produces a neap tide. A
  neap tide is the lowest possible high tide.

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Essential Question - Answered

• What causes the tides?
• Tides are caused by the moons gravity pulling
  Earths water towards it.
• Complete remaining notes.