1. Sun, Earth, Moon System

2. The Earth Spherical Shaped…
…with a slight bulge at the equator and slightly flattened poles
Humans first believed the Earth was flat
Aristotle first suspected that Earth was a sphere based on observations made during an eclipse
Sailors also thought Earth was spherical based on observations at sea of other boats and of the stars
"Nasa blue marble" by NASA/ GSFC/ NOAA/ USGS - Licensed under Public Domain via Wikimedia Commons -

3. The Earth Rotates
Rotation: Earth rotates on its axis, an imaginary line on which it spins
Causes night and day
Rotates every 23 hrs. 56 min. 4 sec. (sidereal day)
A solar day is 24 hours

4. Magnetic Poles
Thought to be created by a combination of the Earth’s core and rotation
The magnetic north pole is different from the geographical north pole (where the earth rotates)
The magnetic north pole is 11.5° off from the geographical north pole

5. Seasons The Earth’s yearly orbit around the sun: Revolution
Earth’s orbit is NOT a circle, it is an ellipse (elongated, closed curve)
The Earth is closest to the sun on January 4 and furthest from the sun on July 4.
The tilt of the Earth’s axis, in combination with its orbit, causes the seasons
When the Earth is tilted toward the sun, it is summer
When the Earth is tilted away from the sun, it is winter
It is the opposite season in the southern hemisphere because when we’re pointed toward the sun, they are pointed away, and vice versa

6. Seasons

7. Solstices
The solstices occur when the Earth is pointed completely toward or away from the sun
The summer solstice (around June 21) is the longest day in the northern hemisphere. This is the day that the Earth is pointed most toward the sun. The sun travels directly over the Tropic of Cancer, located at 23.5° north latitude.
The winter solstice (around December 21) is the shortest day in the northern hemisphere. This is the day that the Earth is pointed most away from the sun. The sun travels directly over the Tropic of Capricorn, located at 23.5° south latitude.

8. Summer Solstice
"Earth-lighting-summer-solstice EN". Licensed under CC BY-SA 2.0 via Wikimedia Commons -

9. Winter Solstice
"Earth-lighting-winter-solstice EN". Licensed under CC BY-SA 2.0 via Wikimedia Commons -

10. Equinox
The spring (around March 21) and fall (around September 21) equinox occurs when the sun travels directly above the Earth’s equator. On these days, the equator receives exactly 12 hours of daylight and 12 hours of darkness.
The solstices and equinoxes begin each season.

11. Equinox
"Earth-lighting-equinox EN". Licensed under CC BY-SA 2.0 via Wikimedia Commons -