1. HOW DOES THE EARTH MOVE?

2. Try and explain what you see here. Why has this happened
Try and explain what you see here. Why has this happened? What is causing this weird circular pattern?

3. Earth’s Rotation:
Earth rotates on its axis once every 24 hours (15o/hr)

5. Earth rotates in a counterclockwise direction
Earth rotates on its axis, at an angle of 23 ½ degrees

7. Earth’s Revolution
Earth revolves around the Sun once every 365 days

8. Earth’s orbit is described as a slightly eccentric ellipse
When (season)is earth closest to the sun?
Earth is closer to the Sun in the winter and further away in the summer!

9. How do planets stay in their orbits?
Gravity is a strong attractive force between objects
Why is this shape wrong????

10. The more massive two objects are, the greater the gravitational force between them
The closer the two objects are to each other, the greater the gravitational force between them

11. Therefore..
As planets move closer to the Sun, their orbital velocity (speed) increases

12. Inertia:
Earth does not get pulled into the Sun because of Inertia

13. An object in motion will continue moving in a straight line at a constant speed unless acted upon by a force – GRAVITY!

14. Reason for Seasons

16. 1. Tilt of Earth’s Axis Earth’s axis is tilted at 23 ½ degrees
During the summer, the northern axis is tilted towards the Sun

17. During the winter, it is tilted away from the Sun
If it were tilted more than this, our seasonal weather would be more extreme (hotter summers and colder winters)

18. Towards
Away
Further
Closer
June 21
Dec. 21

20. 2. Revolution around Sun
Earth orbits the Sun in an slightly elliptical shape

21. Summer Solstice June 21st
Earth’s northern axis is tilted towards the Sun
Sun has the highest and longest path in the sky in NYS
15 hours of daylight and 9 hours of darkness

22. Seasons
Seasons

23. 23

24. Winter Solstice 9 hours of daylight and 15 hours of darkness
December 21st
Earth’s northern axis is tilted away from the Sun
Sun has the shortest path in the sky in NYS
9 hours of daylight and 15 hours of darkness

25. Seasons
Seasons

26. 26

27. Equinoxes March 21st and Sept. 21st
12 hours of daylight and 12 hours of darkness (equal)

31. The Moon

35. The Moon The Moon orbits the Earth in ~ 28 days (one month)
The Moon also rotates on its axis

36. Why do we weigh less on the moon?

38. Moon Phases The moon reflects the suns light
Half is always illuminated

39. As the Moon revolves around the Earth, we see different parts of the illuminated half
Because of this, we have moon phases

40. Moon Phase Animation