Aim: Why do we get seasons?

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

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

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.

June

December

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

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.

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

Equinoxes

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

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