1. Why do we have seasons? https://www.youtube.com/watch?v=b25g4nZTHvM

2. What Causes the Seasons?
The earth’s orbit – revolution around the Sun- - is inclined 23.5 degrees from the horizontal plain, is the cause for the change in seasons

3. Earth’s rotation
The Earth rotates on its axis (imaginary vertical line around which Earth spins) every 23 hours & 54 minutes.
Varying amounts of sunlight create seasons
The Earth’s AXIS is the most important reason we have seasons

4. The Earth ROTATES daily The Earth REVOLVES around the Sun
Earth’s revolution
It takes the Earth 365 days (or rotations) to travel or revolve around the Sun once.
This is called a
year.
The Earth ROTATES daily
The Earth REVOLVES around the Sun

5. Earth’s Orbit
The Earth’s orbit around the sun is NOT a perfect circle.
It is an ellipse.
Seasons are not caused by how close the Earth is to the sun.
The Earth is closest to the sun around January 3 and farthest away from the sun around July 4.
Ellipse

6. Why is it colder in winter, and warmer in summer?
Rays hit Earth at a steep angle
Earth leans toward the Sun in summer
Hemisphere tilted toward the Sun
Winter
Rays hit at a shallow angle
Rays are more spread out minimizing energy to Earth
Less daylight and longer nights

7. Solstices
Solstices occur twice a year, when the tilt of the Earth's axis is oriented directly towards or away from the Sun, causing the Sun to appear to reach its northernmost and southernmost extremes.
Winter solstice is the shortest day of the year- December 21st
The Summer Solstice is the longest day of the year - June 21

8. Equinoxes
A day lasts 12 hours and a night lasts 12 hours at all latitudes.
Equinox literally means "equal night".
Sunlight strikes the earth most directly at the equator.
This occurs twice a year.
Spring (vernal)– March 21
Fall (autumnal) – September21

9. Summer is warmer than winter (in each hemisphere) because the Sun's rays hit the Earth at a more direct angle during summer than during winter

10. Winter – Indirect sunlight
Summer – Direct sunlight

11. Seasons…in a nut shell

12. Review Look closely at where the Sun is hitting the Earth during each season:
FALL
WINTER
SUMMER
SPRING

17. Finish notes paper