1. what are the 3 spheres of earth?
a.
b.
c.
2. which of the 3 spheres of earth contains the most mass?
3. complete the chart:
type of force definition examples
constructive force
destructive force
4. define atmosphere.


5. what gasses, and what percentages, make up earth atmosphere?
a.
b.
c.
6. define gravity.


7. what two factors affect gravity?
a.
b.
8. what two things keep the earth and moon in their orbits?
a.
b.
9. define revolution.


10. how long is earth’s revolution?
11. define rotation.


12. how long is earth’s rotation?
13. what location(s) on earth receive the least sunlight due to the tilt of the axis?
14. what causes day and night?
15. describe the moon’s surface.


16. what side of the moon is visible from earth?
17. why do we on earth never see the far side of the moon?


18. what are the phases of the moon? draw the phases in this blank space below.
a.
b.
c.
d.
e.
f.
g.
h.
19. during which phases of the moon does a lunar eclipse occur?
20. what is the shortest amount of time that could occur between a lunar eclipse and a solar eclipse?
21. what affects earth’s tides?
22. what occur between earth, moon, and sun that causes earth’s tides to be the highest?

23. how does a neap tide occur?

24. how long does it take the moon to progress through all its phases?
25. go back to #18, on the arrows, write the time it takes to go from phase to phase.
26. explain what happens during a lunar eclipse.


27. explain what happens during a solar eclipse.