Water Lessons

4. A large, flowing body of water that usually empties into a sea or ocean
6. A large body of water surrounded by land
8. The part of the ocean floor that is closest to the land and not very deep
9. The outermost layer of the Earth that lies beneath the ocean
10. The area of land drained by a river and its branches
11. Hot fluid or semi-fluid material below or within the earth's crust from which lava and other igneous rock is formed by cooling
13. A theory that explains how new oceanic crust forms at mid-ocean ridges and moves away from those ridges to create new seafloor

1. Structures built across a river to control its flow and use it to generate electricity
2. Currents move water in a certain direction
3. The act of making air, water, or land dirty and unsafe to use.
5. A very large area of salt water, covering most of the Earth
7. A mountain with a hole on top that can erupt, spewing out lava and ash
12. A huge, slow-moving sheet of ice