Back to Earth

1. What is the name of solid outer shell of the earth? The Lithosphere
2. The Earth's crust is broken up into _9_ huge plates.
3. The Earth's core is a 1km sphere of solid _Fe_ surrounded by molten metals.
4. The temperature of Earth's core is approximately _7000 F_.
5. Heat moves from the interior of Earth to the exterior of the Earth by _convection_ currents.
6. 18,000 meteorites per year enter Earth's atmosphere. Most of the meteorite burns away but some of it may strike the ground. The remains of the meteorite are called _Chondrites_.
7. What very rare element is found in extremely high concentrations around meteorite impact craters? Iridium
8. Magma that has cooled on the surface of Earth forms an extremely dense hard rock called _basalt_.
9. The Mid-Atlantic Ridge is exposed on land in _Iceland_.
10. The world’s tallest land-based mountain range, formed by the collision of India and China, is called the _Himalayas_.
11. Hydrothermal vents on the bottom of the ocean that expel minerals and super heated sea water are called _black smokers_.
12. The island of Surtsey suddenly erupted from beneath the surface of the Atlantic Ocean in 1964. Surtsey is located off the coast of what country? Iceland
13. Approximately _10%_ of the world's population lives within sight of an active volcano.
14. Which west coast city is considered most at-risk of a catastrophic earthquake? Los Angeles
15. A fault that lies deep in Earth and has not been found is called a _blind_ fault.
16. What are the caves found on islands that are fresh water on the top and saltwater in the depths called? Blue Holes
17. The most powerful force in nature on the planet is _water_.
18. Mass extinctions occur on average about every _30 million years_.
19. There are at least _200_ identified asteroids on path to cross Earth's orbit.
20. Our sun will die in approximately _5 billion years_.
21. 200 million years ago, all of the land was grouped together in one huge mass called _Pangaea_.
22. The movement of heat and materials within Earth causes the tectonic plates to move. The movement of the plates and the continents attached to them is called _continental drift_.
23. The _Mid-Atlantic Ridge_ runs along the bottom of the Atlantic Ocean and is where sea floor spreading occurs.
24. The rocks found in Australia are a deep red color. The color comes from rust. Rust is formed when the elements _Fe_ and _O_ chemically react.
25. The _San Andreas Fault_ is the major boundary between the Pacific plate and the North American plate and runs from Mexico to Oregon along the Pacific coast?
26. Lighter continental plates plunge beneath heavier plates in areas called _subduction zones_.
27. (N)Nitrogen, (S)Sulfur and (O)Oxygen combine with H2O in the atmosphere to form _acid rain_.
28. The Pacific plate is moving in a _NW_ direction and the North American plate is moving in a _SE_ direction. 
29. A _rock icicle_ is a common name for Stalactites and Stalagmites .
30. 65 million years ago a 10 km diameter asteroid slammed into the Atlantic ocean creating a 110km wide crater off the coast of _Mexico_. ( What Country?)