Chapter 8 quiz

4. If no one has ever visited the core of the Earth, how do we know that it is made of metals?

b. circulating liquid metals in the core set up a large (measurable) magnetic field

5. The type of rock we find predominant in the crust of the Earth's continents is called:

b. granite

23. Which of the following points about our planet's atmosphere is FALSE?

b. its mass is a substantial part of the mass of the Earth

6. Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth's layers to happen?

c. the early Earth must have been so hot it was like a liquid and heavier things sank to the middle

26. An increase in the Earth's temperature by several degrees Celsius would result in:

c. the melting of many glaciers, a rise in sea levels, and more flooding of towns near the coasts of the continents

20. In which region of the Earth's atmosphere have you spent most of your life?

c. the troposphere

25. Today, a significant amount of new gas is joining the atmosphere of the Earth from what source:

c. volcanoes release gas that was trapped within the Earth

. An important way that scientists have been able to study the interior of the Earth is by:

d. measuring how seismic waves are transmitted through the Earth

14. Earthquake producing faults are much more likely to be found

d. on the boundaries of continental plates, where they meet other plates

11. Rocks that have not been chemically modified by being significantly heated are called

d. primitive

8. Which of the following statements about the Earth's magnetosphere is FALSE?

e. its shape and size are the same on the sides facing toward and away from the Sun

24. The most abundant gas in the Earth's atmosphere is

e. nitrogen

12. According to the theory of plate tectonics,

e. slow motions within the mantle of the Earth move large sections of the crust around

19. For scientists, one bar is

c. the average height of the ozone layer above the Earth (before we began to deplete it)

9. The Van Allen belt is

a. a region of trapped charged particles in the Earth's magnetosphere

27. Today, scientists believe that the main reason the Earth has had periodic ice ages is:

a. slow changes in the tilt of our planet's axis of rotation

7. The region around the Earth where charged particles are trapped and spiral around is called:

a. the magnetosphere

15. The process of convection involves

a. the slow upward flow of warmer material and downward flow of cooler material

29. Which of the following is a way we believe that the early atmosphere of the Earth differed from the atmosphere we have today?

a. there was little if any free oxygen early on b. there was no ozone layer early on c. there was probably more carbon dioxide early on than there is today d. all of the above

16. A spot where magma rises to the surface can be seen as a

a. volcano

31. The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?

b. carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect

13. Regions where the continents or the sea floor are pulling apart are called

b. rift zones

18. Mountains on Earth often have sharp peaks and edges to them, while mountains on the Moon look smooth and kind of dull in comparison. What gives the Earth's mountains their dramatically sharp shapes?

b. water and ice flow over the Earth's mountains and erode them

10. Any rock in the Earth's crust that has cooled from an originally molten state is called

c. igneous

he largest part of the Earth is its

c. mantle

30. In terms of numbers, the most common life-forms on Earth are

c. microscopic creatures, too small to see with our eyes

22. Scientists have been concerned about a set of industrial chemicals called CFC's (chlorofluorocarbons) because they:

c. rise into the atmosphere and destroy ozone

17. The person who came up with the continental drift theory that led to our modern understanding of plate tectonics was

d. Alfred Wegener

28. According to the fossil record, how old is the oldest evidence of life forms on the surface of the Earth?

d. about 3.5 billion years

21. One way in which the ozone layer is useful for life forms on the Earth's surface is that it

d. absorbs ultra-violet light, preventing much of it from reaching the surface

3. Which part of the Earth has the greatest density?

d. core