Plate tectonics

5. Earth’s outermost layer of hard, solid rock that is underneath the soil, vegetation, and water
7. when two plates are moving apart from each other
8. these often happen at convergent boundaries when two plates colide
9. these happen often at a divergent boundary when the mantle is coming up between two plates
11. When two plates move together and one goes under the other
12. a set of interacting parts forming a complex whole
14. There are 12 on earth
16. the layer under the land and ocean
17. The person who invented the theory of plate tectonics
18. The name of the puzzle
19. an object, diagram, or computer program that helps us understand something by making it simpler or easier to see

1. something we observe to be similar over and over again
2. any of the many processes (such as eruptions and lava flows) in which gas, lava, and ash are pushed out on the surface of Earth
3. when two plates slide next to each other
4. Underwater mountain range formed when two plates move apart
6. our teacher
10. the outside or top layer of something
13. The planet we live on
15. a feature that forms on the surface of a planet, such as a mountain, channel, or sand