1. Aim: Why do we get seasons?

2. Seasons & Sun's Distance
Figure 3.1
Earth's surface is 5 million kilometers further from the Sun in June than in December

3. Tilt
Because of the tilt of Earth’s axis, the amount of radiation received by Northern and Southern Hemispheres varies seasonally
The Earth is tilted 23.5 degrees on its axis

4. Hemispheres and seasons
The Northern and Southern hemispheres experience opposite seasons.
It is summer when the pole is tilted towards the sun and winter when the pole is tilted away.

5. June

6. December

7. Summer Solstices The longest day (hours of sunlight) of the year.
Sun is directly overhead at 23.5 deg N the tropic of cancer.
In the N.H. The sun rises North of East and sets north of West meaning that it is in the sky longer

9. Winter Solstice Shortest day (in hours of daylight) of the year.
Sun is directly overhead at 23.5 deg S the tropic of capricorn
The pole is pointed away from the sun.
In the N.H. the sun rises south of east and sets south of west.

11. Equinoxes Autumnal and Vernal or fall and spring
12 hours of daylight everywhere
Sun rises in the east and sets in the west

12. Equinoxes

13. 24 Hours of Daylight
Figure 3.4
Summer north of the artic circle will reveal a period of 24 hour sunlight - a midnight sun.

14. The Sun’s Path
The sun’s path or rising and setting locations changed based on the season.
In the summer the sun rises north of east, in the winter it rises south of east and on the equinoxes rises due east