Plate tectonics

3. There are 12 on earth
4. the outside or top layer of something
5. Underwater mountain range formed when two plates move apart
9. The person who invented the theory of plate tectonics
10. Earth’s outermost layer of hard, solid rock that is underneath the soil, vegetation, and water
14. when two plates slide next to each other
16. a feature that forms on the surface of a planet, such as a mountain, channel, or sand
17. The name of the puzzle
18. hot liquid rock on the surface of Earth
20. these often happen at convergent boundaries when two plates colide

1. something we observe to be similar over and over again
2. When two plates move together and one goes under the other
6. when two plates are moving apart from each other
7. an object, diagram, or computer program that helps us understand something by making it simpler or easier to see
8. these happen often at a divergent boundary when the mantle is coming up between two plates
11. our teacher
12. the layer under the land and ocean
13. The planet we live on
15. the layer of soft, solid rock underneath Earth's plates
19. 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
21. a set of interacting parts forming a complex whole