1. Reason for the Seasons

2. Seasons. . . Are NOT caused by our distance from the sun.
In fact the northern hemi. has summer when it’s winter in the southern hemi.

3. So what causes season then?

4. Seasons occur because
The Earth’s axis is tilted 23.5o and ALWAYS points towards the North star

5. This changes: The time we spend in the sunshine
How high the sun is in the sky
The angle the sunlight hits Earth.

6. In the summer the rays are more direct, intense, and warm
In the summer the rays are more direct, intense, and warm. In the winter the same number of rays are spread over a larger area so they are thinner and less warm.
Summer light
Winter light
More area has to “share” the same amount of light/heat in the winter

7. This changes the amount of heat we get during the year.

8. Therefore, seasons are caused by the TILT OF THE EARTH!

10. Summer Solstice= axis pointed to sun: longer days, concentrated rays, warmer

11. Winter Solstice = Axis points away from the sun: more darkness, sunlight’s spread out, cooler.

12. Spring and fall equinox= axis is parallel to sun: whole Earth receives equal energy.

15. Seasons. . .
Change every 3 months around the 20th. (March, June, September, and December)