Plate tectonics

1. There are 12 on earth
3. The person who invented the theory of plate tectonics
6. the layer under the land and ocean
8. 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
10. The name of the puzzle
12. Underwater mountain range formed when two plates move apart
13. the outside or top layer of something
14. the layer of soft, solid rock underneath Earth's plates
16. when two plates are moving apart from each other
17. when two plates slide next to each other
20. a feature that forms on the surface of a planet, such as a mountain, channel, or sand
21. an object, diagram, or computer program that helps us understand something by making it simpler or easier to see

2. our teacher
4. hot liquid rock on the surface of Earth
5. these often happen at convergent boundaries when two plates colide
7. a set of interacting parts forming a complex whole
9. When two plates move together and one goes under the other
11. The planet we live on
15. something we observe to be similar over and over again
18. Earth’s outermost layer of hard, solid rock that is underneath the soil, vegetation, and water
19. these happen often at a divergent boundary when the mantle is coming up between two plates