Video Review Question Set Earth Revealed – Earth’s Interior
Watch the video and answer the following review questions.
ANSWER KEY
1. At what temperature does the soviet well penetrate at?
Pressure 5,000 out of earth’s surface with temp 300 degrees celsium.
2. What examples of geophysics use to study the behavior of interior of earth?
Studying seismic vibrations, analyzing variations in earth temp, magnetic field and gravity, and using
models to know what the conditions are in the earth.
3. Describe seismic waves.
Comparable to sound waves in air, They are traveling through body of earth from a source of waves to
points of body of earth.
4. How many dimensions do seismic waves travel at? List them.
3, one reflects and returns to the surface. This is found out by depth. The second however, may go
through the boundary. The direction will change with bending/refracting.
5. True or False: Earthquakes aren’t the only source of seismic waves.
True.
6. True or False: One can make artificial seismic waves at earth’s surface by other devices.
True.
7. What layers is the earth made up of?
The crust. Skin. Mantle, Thick shell of rock, extending to the Core.
8. How large is the core.
Half the diameter of the planet.
9. True or False: Granitic rock is lying underneath the ocean basins.
False. Granitic is under the continents.
10. How thick are the continents? And Oceanic?
25-40 km thick, Oceanic 5-10 km thick.
11. What rocks are made up of continental crust?
Igneous rocks, sedimentary, and metamorphic rocks combining into all one.
1
12. True or False: Oceanic crust is more uniform than continental crust.
True.
13. What are xenolith’s?
Rock fragments that come deep within the earth’s mantle.
14. True or False: Gabbro rocks are produced with very lo silica.
False. Produced with rich amount of silica.
15. What direction does a P-wave move?
Vibrates parallel to direction of movement.
16. What direction does the S-wave move?
Moves perpendicular to its path.
17. What wave can pass through gas and liquid waves?
P-waves only. S-waves can only through rock.
18. True or False: S-waves are able to pass through earth’s core.
False. None can.
19. What is the earth’s core mostly made of?
Iron with other elements.
20. What do geophysicists use when they want to measure the force of gravity?
A gravimeter.
21. True or False: The earth’s mantle rock is less dense than a crustal rock of the earth.
False. It is denser than the crustal rock.
22. What way does loadstone normally point if it were to be put on wood?
North.
23. What did Fereideigh invent to show that there was a connection with electricity and magnetism?
A deivice with electic current moving in circuluar motions.
2
24. What produces fluid motion and convection currents?
Heat from earth’s core.
25. How is the aurora borealis created?
The solar wind is deflected from earth by earth’s magnetic field but being magnetic; they hit the
atmosphere and cause gases to glow forming the aurora.
26. True or False:
The strength of earth’s field had increased in strength over the last 150 years. False. I have decreased
about 5% in last 150 years.
27. How and why does the magnetic field reverse itself?
The baked soils under the lava were deep within the ground meaning there was pull a different direction
rather than just north?
28. How many times does the earth’s magnetic field reverse?
Once ever 500,000 years.
29. When a magnetic reversal occurs, how much does it decrease in intensity and in value?
10-20 of its normal value and intensity.
30. What year did the field of intensity start decreasing?
1832.
3