1. Reasons for the Seasons
Let’s Review

2. Activity 1: Temperatures Around the World
A location’s latitude determines its temperature trend during the year.
Locations at or near the equator experience very little change in their temperature.
Locations at higher altitudes near the poles experience a greater change in temperature.
Opposite hemispheres = opposite patterns.

3. Activity 2: Days and Nights Around the World
A location’s latitude determines how much daylight it gets at different times during the year.
Locations near the equator experience approximately 12 hrs of daylight and 12 hrs of darkness all year.
Locations closer to the poles at higher latitudes experience a wide range of day lengths.
Opposite hemispheres = opposite patterns

4. Activity 3: Tilted Earth
Rotation – when an object turns about on its axis. It takes Earth 24 hours to rotate on its axis (1 day).
Revolution – when one object moves in a path around another object. It takes Earth days to revolve around the Sun (1 year)
Earth’s axis is tilted at 23.5 degrees toward the North Star.

5. Activity 3: Tilted Earth
Winter Solstice – shortest day of the year. (Dec. 21st for N. Hemisphere)
Summer Solstice – longest day of the year. (June 21st for N. Hemisphere)
Equinox – when there is an equal amount of daylight and darkness.
Spring (Vernal) Equinox = March 21st
Fall (Autumnal) Equinox = Sept. 21st

6. Activities 3 & 4: Tilted Earth & Solar Angle
During the winter, the hemisphere is tilted away from the Sun, resulting in a low solar angle, a shorter day, and receiving less direct sunlight.
During the summer, the hemisphere is tilted toward the Sun, resulting in a high solar angle, receiving more direct light, and therefore a longer amount of daylight.
Distance to the Sun has no affect on our Seasons!

7. Sun-Earth Survey Answers
1. A. The Earth’s orbit is close to circular, so our distance to the Sun does not vary much and does not affect our seasons. (We are actually closest in the beginning of Jan. and farthest the beginning of July)
2. C. is correct, because it most accurately represents the great distance between the Earth & Sun and the great difference in sizes of the two.

8. Sun-Earth Survey Answers
Question 3:
A = NOT correct. The Sun’s variation in energy output does not correlate with our seasons.
B = NOT correct. The distance does not change very much and does not correlate with our seasons.
C = NOT correct. Because we are a sphere, our tilting axis does not make us any closer/farther.

9. Sun-Earth Survey Answers
Question 3:
D = CORRECT! Because we are tilted towards the Sun in summer, we receive longer amounts of daylight which give us increased temperatures (Think – Activities 5 & 6)
E = CORRECT! Because we are tilted towards the Sun in summer, the Sun is at a higher solar angle and therefore we receive more direct sunlight.

10. Sun-Earth Survey Answers
Question 3:
F = NOT correct. The Moon has nothing to do with our seasons.
G = CORRECT! We do receive more hours of sunlight in June in the United States, therefore increasing our temperatures.