1. Moon
Sun
Gravity
Near and Far

2. Day and Night

3. Star
Erosion
Weathering
Soil

4. Weather
Natural Resources
Ocean
River

5. Lake
Stream
Drought
Flood

6. Volcano Eruption
Earthquake
Thunderstorm

7. Humus
Clay
Sand
Boulder

8. Pebble
Precipitation
Gas
Evaporation

9. Condensation

10. Revolve
Rotate
Igneous Rock
Metamorphic Rock

11. Sedimentary Rock
Mineral
Luster
Cleavage

12. Streak
Luster
Hardness
Constellation

13. Moon Phases
Season
Satelite
Axis

14. Nonrenewable Resources
Space Probe
Orbit
Renewable Resources
Nonrenewable Resources

15. Asteroid
Comet
Solar System
Hemisphere

16. Climate
Humidity
Polar Zone
Temperate Zone

17. Water Cycle
Water Vapor
Polar Zone
Galaxy

18. Milky Way
Inner Planets
Outer Planets
Meteor

19. Meteoroid
Meteorite
Elevation
Front