1. Day and Night World Map

2. On the back of your graph… In complete sentences…
How does a city's latitude affect the number of daylight hours that were recorded during a one year period?
How does the Earth’s tilt affect the number of daylight hours during different seasons in the northern and southern hemispheres?

3. Areas near the Equator receive a more constant amount of approximately 12 hours of daylight each day. Higher or lower latitudes have more variance.
The Earth’s tilt results in a change in the amount of daylight an area of Earth receives each day. As you move away from the Equator towards the Poles, the change gets greater.

4. Length of Days & Nights Seasons
Cycles of the Sun
Length of Days & Nights
Seasons

5. Length of Days & Nights The Earth rotates on its axis
A complete rotation takes a little over 24 hours (1 day)
One side of the Earth is always facing the Sun

6. Length of Days & Nights The side of the Earth facing the Sun has day
The side of the earth facing away from the Sun has night

8. As the Earth Rotates…
The side of the Earth in the sunlight spins away and becomes night
The side of the Earth in the dark spins toward the Sun and becomes day

10. Changing Length of Day & Day
The number of hours of daylight received each day depends on the latitude.
The equator receives about 12 hours of daylight all year long

11. Changing Length of Day & Day
The hemisphere that is tilted toward the Sun gets more hours of daylight that the hemisphere tilted away from the Sun
Latitudes closest to the equator have less change in hours of daylight
Latitudes further from the equator have more dramatic changes in hours of daylight

13. Seasons
The Earth is tilted on its axis

14. Seasons
The tilt does not change – it always remains pointed in the same direction

16. Seasons
As the Earth revolves around the Sun, the tilt sometimes points toward the Sun, sometimes away from the Sun, and sometimes neither away nor toward the Sun

18. Seasons The hemisphere that is tilted toward the Sun has summer
Longer days (more hours of sunlight)
Warmer weather

19. Seasons The hemisphere that is tilted away from the Sun has winter
Shorter days (less hours of sunlight)
Cooler weather

20. Seasons
When the Earth is positioned so that the tilt is neither towards nor away from the Sun, we have Spring and Fall
Moderate temperatures
Days and nights of similar length

22. Seasons: Summer (Northern Hemisphere)
Position of the Earth is such that the northern hemisphere is tilted toward the Sun
Summer Solstice (1st day of summer)
Sun at highest point (over Tropic of Cancer)
Most hours of sunlight (longest day)
About June 21

24. Seasons: Fall (Northern Hemisphere)
Position of the Earth is such that the northern hemisphere is tilted neither towards nor away from the Sun
Autumnal Equinox (1st day of fall)
About 12 hours of sunlight
About September 22

26. Seasons: Winter (Northern Hemisphere)
Position of the Earth is such that the northern hemisphere is tilted away from the Sun
Winter Solstice (1st day of winter)
Sun at lowest point (over Tropic of Capricorn)
Fewest hours of sunlight (shortest day)
About December 21

28. Seasons: Spring (Northern Hemisphere)
Position of the Earth is such that the northern hemisphere is tilted neither towards nor away from the Sun
Vernal Equinox (1st day of spring)
About 12 hours of sunlight
About March 21

30. Energy from the Sun (Insolation)

32. Summing Up:
Winter - Earth tilted away from Sun, fewer hours of sunlight, less direct sunlight (insolation)
Spring – Earth neither tilted away nor toward the Sun, equal hours of daylight and night
Summer – Earth tilted toward the Sun, more hours of daylight, more direct sunlight (insolation)
Fall - Spring – Earth neither tilted away nor toward the Sun, equal hours of daylight and night

33. Watch this animation: http://www. shsu

34. Works Cited