1. The Sun & Gravity

2. Have you ever noticed that the sun travels lower across the sky in winter than in summer? This is because Earth is tilted on its axis at a 23.5o angle.
Seasons
During winter part of Earth tilts away from the sun. This causes the sun’s rays to strike that part of Earth at a lower angle than in the summer.

3. Seasons- Remember it’s the TILT of the Earth that causes the seasons

4. Winter Solstice- shortest day of the year
Days are shorter & nights are longer during winter. This occurs in December in the Northern Hemisphere & in June in the Southern Hemisphere.
Each hemisphere receives less sunlight & therefore less heat energy during the winter. This is why temperatures are colder during winter.

5. Summer Solstice- longest day of the year
This occurs in June in the Northern Hemisphere and in December in the Southern Hemisphere.
Earth’s revolution around the sun causes part of the Earth to tilt toward the sun at different times of the year. This causes that part of the Earth to receive more sunlight at a more direct angle. This is why days are longer and nights are shorter.

6. Equinox Equinox- means “Equal Night”
Daytime lasts exactly as long as nighttime on the first day of autumn – the Autumnal Equinox (about September 21) and the first day of spring - the Vernal Equinox (about March 21).