crossword review

7. age compared to other rocks Determined by stratigraphy
8. a disturbance in a medium that carries energy without a net movement of particles
9. age of a rock in years. Determined by radiometrics.
11. the ability to do work
16. what erupted in June 1883
17. Two forces thrusting in opposite directions
18. at the center of our solar system.

1. a push or pull upon
2. a boundless, three-dimensional extent in which objects and events occur and have relative position and direction.
3. keeps planets in orbit around the sun.
4. A giant cloud in space.
5. form of energy
6. the large round object that circles the Earth and that shines at night by reflecting light from the sun.
10. Opposite of compression. Force which pulls away from the center
12. the solid mineral material forming part of the surface of the earth and other similar planets exposed on the surface or underlying the soil or oceans.
13. the state of the atmosphere at a place and time as regards heat, dryness, sunshine, wind, rain,
14. planet that is the third in order from the sun.
15. is molten rock that has been expelled from the interior of a planet or Compression Force pushes towards the center of an object.
17. vibrations that travel through the air or another medium and can be heard when they reach a person's or animal's ear.