1. Rotation and Revolution

2. Astronomy:
The study of objects in space

3. Astronomy:
Includes Earth

4. Astronomy:
Moon

5. Astronomy:
Solar System

6. Astronomy:
Stars

7. Astronomy:
Galaxies

8. Astronomy:
Universe

9. Day
The side of the Earth that is facing the Sun and is illuminated by its light
Note: definition says nothing about time!

10. Night
The side of the Earth that is facing away from the Sun and is not illuminated by its light

11. Terminator The line marking the change between day and night.
This is dawn and dusk

12. Video: Day and Night

13. Rotation

14. Rotation
The movement or path of the earth or a heavenly body turning on its axis

15. Video: NASA-Rotating Earth

16. Rotation
Causes day and night
1600 km/hr at the Equator

17. Rotation
Rotates from West to East

18. Rotation
Sun appears to move East to West
west east

19. Rotation Takes approximately 24 hours
24 hour period is also called a day

20. Video: Movement of the Earth

21. Year
The time it takes for the Earth to go around the sun one complete revolution
Approximately days

22. Revolution The movement of one object around another
The planets revolve around the sun

23. Orbit The path of an object as it revolves around another
Earth’s orbit around the Sun is a slightly flattened circle (ellipse)

24. Seasons
The yearly cycle of changes in the angle at which sunlight hits the surface of the planet

25. Seasons Seasons are caused by the tilt of the Earth’s axis
23.45o from vertical
The earth spins like a wobbly top

26. Seasons
This tilt means that sunlight hits the surface at different angles at different times of the year