What causes the seasons on the Earth?

• The seasons of the Earth are caused by the revolution of the Earth around the Sun on an angular, _______ degree tilt. This causes:
  • The hours of __________ to vary.
  • The intensity of sunlight to change. The ________ the sun gets in the sky, the more concentrated the sunlight.
• When the Northern Hemisphere is experiencing a season, the _________________ season is occurring in the Southern Hemisphere!

SUMMER

• When the North Pole is tilted toward the sun, we experience ___________.
• The sun is directly overhead at the Tropic of ____________, 23.5 degrees N.
• The sun's rays become more concentrated on the Northern Hemisphere resulting in __________ temperatures.
• In New Paltz, there are double the hours of ___________ than winter!

WINTER

• When the South Pole is tilted toward the _______, we experience winter.
• The sun is directly overhead at the Tropic of _____________, 23.5 degrees S.
• The sun's rays become more concentrated on the Southern Hemisphere resulting in __________ temperatures.
• A day only lasts 8 hours in __________!
• When we are experiencing winter we are actually closer to the sun by 3 __________ miles!!!

SPRING AND FALL

• At solar noon the sun's rays hit the ___________, 0 degrees latitude, causing everywhere on Earth to have 12 hours of day and 12 hours of night!
• A side view of the Earth during the equinox looks like this:

The Sun's Path

The apparent path of the sun is an arc and it changes with the seasons. Some facts we can observe about the sun's path are:

• The sun appears to rise in the _______ and set in the ________ .
• Stars and the moon also appear to rise in the _______ and set in the ________ .
• Of course, the sun, stars and moon aren't moving, WE are rotating!!!
  • How fast are we spinning?
    • Number of degrees in a circle: ________
    • Number of hours in a day: __________
    • Degrees of rotation per hour: ________
• If you were in space, looking down at the North pole, the Earth spins counterclockwise.

Sun's Path in New Paltz

• The sun is NEVER directly __________ in New Paltz.
• The highest the sun ever reaches is _____ degrees above the horizon on ____________ solstice.
• The sun is always due _______ at solar noon (when the sun is highest in the sky).
  • Below the equator, the noon sun is always due North!!

The sun's path changes with your latitude.

• At what latitude would the sun be overhead at solar noon on March 21? __________
• When would the sun be directly overhead at 23.5 degrees south? __________
• In what month is the sun overhead at solar noon at the Tropic of Cancer? ___________
• What hemisphere of the world would you be in if the noon sun was in the northern sky? ______

Using an instrument called an astrolabe it is easy to find your latitude. The _________________ of Polaris is equal to your _________________ .