Days, Years

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Days, Years Seasons
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Days and Nights

• Rotation the Earth turns around on its axis
• 1 day24 hours (one rotation)
• One half of the Earth is always in light and one
  half is always in darkness
• List some examples of rotation

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Years

• Revolution the Earth moves around the sun
• 1 year365 1/4 days (one revolution)
• List some examples of revolutions

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What REALLY causes the seasons?

• The Earth is tilted as it revolves around the
  sun.

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Seasons (summer, fall, winter, spring)

• The Earths axis is tilted 23 1/2 degrees from
  vertical
• The tilt is always oriented the same way and
  causes the four seasons
• The 23 1/2 degree tilt causes the sunlight to
  follow a different path across the Earths
  surface

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Summer Solstice June 21

• The Earths Northern Hemisphere is tilted towards
  the sun

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Summer Solstice

• More direct energy (heat) enters the atmosphere
• There is 24 hours of daylight at the North Pole
  and 24 hours of darkness at the South Pole
• The longest day of the year
• Aphelion the Earth is the farthest from the sun
  (94 million miles)

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Winter Solstice December 21

• The Earths Northern Hemisphere is tilted away
  from the sun

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Winter Solstice

• The suns energy (heat) is more concentrated in
  the Southern Hemisphere
• There is 24 hours of daylight at the South Pole
  and 24 hours of darkness at the North Pole
• The shortest day of the year
• Perihelion the Earth is the closest to the sun
  (91 million miles)

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What happens when the Earth is not tilted toward
or away from the sun?
HERE
And HERE
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Equinox

• The Earth is not tilted toward or away from the
  sun
• Spring Equinox March 21
• Fall Equinox September 21
• There are 12 hours of daylight and 12 hours of
  darkness from the North Pole to the South Pole
• The distance between the sun and the Northern and
  Southern Hemispheres of Earth are equal!

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Seasons Animations

• http//www1.teachertube.com/viewVideo.php?titleWh
  at_Causes_Seasons_on_Earthvideo_id657
• http//esminfo.prenhall.com/science/geoanimations/
  animations/01_EarthSun_E2.html