CHAPTER 2: Journey to the Center of the Earth

MULTIPLE CHOICE

	1.	If one were to see a comet passing by Earth, it is likely that this comet originated from ________.
a.	the asteroid belt	c.	a neighboring galaxy	
b.	the Kuiper belt	d.	interplanetary space	

ANS:	B	DIF:	Easy	REF:	2.2	TOP:	1
MSC:	Applying

	2.	The region of space that contains all of the material of our Solar System (shown below) is termed the ________.

a.	Kuiper belt	c.	cryosphere	
b.	heliosphere	d.	Oort cloud	

ANS:	B	DIF:	Easy	REF:	2.2	TOP:	1
MSC:	Remembering		

	3.	Where can icy bodies left over from the protoplanetary disk that formed our Solar System long after the Big Bang be found?
a.	heliosphere	c.	Kuiper belt	
b.	Oort cloud	d.	interplanetary space	

ANS:	C	DIF:	Medium	REF:	2.2	TOP:	1
MSC:	Applying

	4.	Which of the following is NOT true about comets and asteroids?
a.	Comets are icy while asteroids are rocky.	
b.	Both are planetesimals.	
c.	Both are numerous in our Solar System.	
d.	Both originate in the Kuiper belt.	

ANS:	D	DIF:	Medium	REF:	2.2	TOP:	1
MSC:	Analyzing

	5.	The shape of Earth’s magnetic field is approximately that of a ________.
a.	monopole, as would be produced by just one pole of a magnet	
b.	dipole, such as that produced by a bar magnet	
c.	torus, a doughnut-shaped ring parallel to Earth’s equator	
d.	sphere, following the shape of Earth	

ANS:	B	DIF:	Easy	REF:	2.2	TOP:	2
MSC:	Remembering		

	6.	Presently, Earth’s atmosphere is dominated by which two gases?
a.	hydrogen and helium	c.	nitrogen and oxygen	
b.	oxygen and carbon dioxide	d.	carbon dioxide and sulfur dioxide	

ANS:	C	DIF:	Easy	REF:	2.2	TOP:	2
MSC:	Remembering		

	7.	If one were to ride a hot air balloon up into the atmosphere, one would experience the concentration of gases ________.
a.	becoming denser	
b.	becoming less dense	
c.	remaining the same	
d.	increasing for the first 10 km, then starting to decline	

ANS:	B	DIF:	Medium	REF:	2.2	TOP:	2
MSC:	Applying

	8.	Earth’s surface is protected from solar wind and cosmic radiation by ________.
a.	Earth’s gravitational field	
b.	Earth’s magnetic field	
c.	a large, metallic shield launched into orbit by NASA in the 1960s	
d.	a powerful stream of ions emitted by the Sun	

ANS:	B	DIF:	Medium	REF:	2.2	TOP:	2
MSC:	Understanding		

	9.	An aurora (shown below) is produced when ________.

a.	solar wind particles are directed toward the magnetic poles and excite atmospheric gases	
b.	swamp gases rise from the arctic tundra and react with the upper atmosphere	
c.	radiation in the Van Allen belts can be seen on a clear, cold night	
d.	lightning travels from cloud to cloud rather than cloud to ground	

ANS:	A	DIF:	Medium	REF:	2.2	TOP:	2
MSC:	Applying

	10.	The atmosphere is divided into several distinct layers. Beginning with the layer in which we live, they are, in order, ________.
a.	stratosphere, troposphere, mesosphere, and thermosphere	
b.	troposphere, stratosphere, thermosphere, and mesosphere	
c.	troposphere, stratosphere, mesosphere, and thermosphere	
d.	stratosphere, troposphere, thermosphere, and mesosphere	

ANS:	C	DIF:	Difficult	REF:	2.2	TOP:	2
MSC:	Remembering		

	11.	Substances that can be transformed to a gas at relatively low temperatures are termed ________.
a.	glasses	c.	volatiles	
b.	melts	d.	mineraloids	

ANS:	C	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Remembering		

	12.	Most continental topography lies within a range of altitude between ________.
a.	sea level and 1 km below sea level	c.	2 to 5 km above sea level	
b.	sea level and 1 km above sea level	d.	3 to 6 km above sea level	

ANS:	B	DIF:	Medium	REF:	2.3	TOP:	3
MSC:	Remembering		

	13.	The most common minerals within Earth are ________.
a.	silicates	c.	oxides	
b.	carbonates	d.	hydroxides	

ANS:	A	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Remembering		

	14.	Hot, liquid rock beneath Earth’s surface is termed ________.
a.	lava	c.	volatiles	
b.	magma	d.	mantle	

ANS:	B	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Remembering		

	15.	Which of the following is NOT required for a substance to be considered a mineral?
a.	It must be solid.	
b.	It must be naturally occurring.	
c.	It must contain carbon.	
d.	It must have atoms arranged in an orderly pattern.	

ANS:	C	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Understanding		

	16.	Most of the ocean floor is made up of ________.
a.	deep-ocean trenches (8 to 11 km below sea level)	
b.	abyssal plains (4 to 5 km below sea level)	
c.	mid-ocean ridges (less than 2.5 km below sea level)	
d.	Elevations of the sea floor are nearly uniformly distributed from sea level to 11 km depth.	

ANS:	B	DIF:	Medium	REF:	2.3	TOP:	3
MSC:	Analyzing

	17.	Which of the following is most representative of Earth’s hydrosphere?
a.	lakes and rivers only	
b.	surficial freshwater, oceans, groundwater, and atmospheric water	
c.	a layer of hydrogen gas in the outer reaches of the atmosphere	
d.	oceans, but not rivers or lakes	

ANS:	B	DIF:	Medium	REF:	2.3	TOP:	3
MSC:	Applying

	18.	In the whole Earth, the four most common elements (by mass) are oxygen, silicon, magnesium, and ________.
a.	copper	c.	iron	
b.	lead	d.	zinc	

ANS:	C	DIF:	Medium	REF:	2.3	TOP:	3
MSC:	Remembering		

	19.	If you were measuring the elevation of a mountain, you would be measuring variation in ________, whereas if you were doing the same on a mid-ocean ridge, you would be measuring variation in ________.
a.	bathymetry; topography	c.	topography; isostasy	
b.	bathymetry; isostasy	d.	topography; bathymetry	

ANS:	D	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Applying

	20.	Glass is different from a mineral because it ________.
a.	is not naturally occurring	
b.	is not a solid	
c.	does not have atoms arranged in an orderly pattern	
d.	contains carbon and is therefore organic	

ANS:	C	DIF:	Medium	REF:	2.3	TOP:	3
MSC:	Understanding		

	21.	Which of the following is NOT an example of sediment?
a.	sand	c.	cobblestones on a beach	
b.	ground-up seashells	d.	sandstone	

ANS:	D	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Applying

	22.	A mixture of copper and tin would be called a(n) ________.
a.	metal	c.	melt	
b.	alloy	d.	volatile	

ANS:	B	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Applying

	23.	A silica-rich igneous rock that has large crystals and makes up much of the continental crust is ________.
a.	peridotite	c.	gabbro	
b.	granite	d.	basalt	

ANS:	B	DIF:	Easy	REF:	2.3	TOP:	3
MSC:	Remembering		

	24.	The density of rocks is generally related to composition. Which of the following choices places rock compositions in order of increasing density?
a.	felsic, intermediate, ultramafic, mafic	
b.	ultramafic, mafic, intermediate, felsic	
c.	felsic, intermediate, mafic, ultramafic	
d.	mafic, ultramafic, intermediate, felsic	

ANS:	C	DIF:	Difficult	REF:	2.3	TOP:	3
MSC:	Applying

	25.	The figure below shows the hypsometric curve for Earth. Which of the following can be concluded from the plot of this data?

a.	Regions of high elevation (> 4 km) are common on Earth.	
b.	Most of the continents are between 0 and 1 km above sea level.	
c.	Elevations of –10 km to 8 km are nearly uniformly distributed across Earth’s surface.	
d.	Most of the sea floor is more than 6 km below sea level.	

ANS:	B	DIF:	Difficult	REF:	2.3	TOP:	3
MSC:	Analyzing

	26.	The image below shows Earth’s magnetic field. Earth’s magnetic field lines are distorted (i.e., not symmetrical) because ________.

a.	Earth is rapidly rotating around the Sun	
b.	Earth is rotating on an internal axis	
c.	convection is occurring in the outer core	
d.	solar wind deflects Earth’s magnetic field lines	

ANS:	D	DIF:	Difficult	REF:	2.3	TOP:	3
MSC:	Understanding		

	27.	Which of the following is NOT true concerning the rocks gabbro and basalt?
a.	Both are common in the oceanic crust.	
b.	Both have small grains/crystals.	
c.	Both are igneous rocks.	
d.	Both are denser than granite.	

ANS:	B	DIF:	Difficult	REF:	2.3	TOP:	3
MSC:	Applying

	28.	Which of the following lists compositions in order of increasing silica content?
a.	felsic, intermediate, ultramafic, mafic	
b.	ultramafic, mafic, intermediate, felsic	
c.	felsic, intermediate, mafic, ultramafic	
d.	mafic, ultramafic, intermediate, felsic	

ANS:	B	DIF:	Difficult	REF:	2.3	TOP:	3
MSC:	Understanding		

	29.	In general, seismic (earthquake-generated) waves travel ________ in the mantle compared to the shallow crust.
a.	faster	
b.	slower	
c.	at the same velocity	
d.	Seismic waves do not travel through the mantle.	

ANS:	A	DIF:	Medium	REF:	2.4	TOP:	4
MSC:	Understanding		

	30.	A fracture in the crust, where rocks slide past one another, is termed a ________.
a.	fold	c.	sliding layer	
b.	fault	d.	joint	

ANS:	B	DIF:	Easy	REF:	2.4	TOP:	4
MSC:	Remembering		

	31.	Earth’s geothermal gradient is the rate of temperature change incurred by ________.
a.	increasing altitude in the atmosphere	
b.	increasing depth at ocean trenches	
c.	traversing from either pole toward the equator	
d.	traversing down within Earth’s interior	

ANS:	D	DIF:	Easy	REF:	2.4	TOP:	4
MSC:	Remembering		

	32.	During a journey to the center of the Earth, one would experience temperature ________.
a.	and pressure both increasing	
b.	and pressure both decreasing	
c.	increasing, but pressure staying nearly the same	
d.	remaining remarkably constant, but pressure increasing	

ANS:	A	DIF:	Easy	REF:	2.4	TOP:	4
MSC:	Understanding		

	33.	The image below shows an example of which type of heat transfer?

a.	radiation	c.	convection	
b.	conduction	d.	advection	

ANS:	C	DIF:	Easy	REF:	2.5	TOP:	4
MSC:	Understanding		

	34.	The densest layer of Earth is the ________.
a.	crust	c.	outer core	
b.	mantle	d.	inner core	

ANS:	D	DIF:	Easy	REF:	2.5	TOP:	4
MSC:	Remembering		

	35.	Compared to oceanic crust, continental crust is ________.
a.	thicker	
b.	thinner	
c.	about the same thickness	
d.	Sometimes continental crust is thicker; sometimes oceanic crust is thicker. There is no consistent pattern.	

ANS:	A	DIF:	Easy	REF:	2.5	TOP:	4
MSC:	Understanding		

	36.	The thickness of Earth’s crust varies from ________.
a.	100 to 500 m	c.	5 to 500 km	
b.	1 to 10 km	d.	7 to 70 km	

ANS:	D	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Remembering		

	37.	Of the three primary compositional layers of the Earth (crust, mantle, core), which is the thickest layer?
a.	crust	
b.	mantle	
c.	core	
d.	The mantle and core are the same thickness.	

ANS:	C	DIF:	Difficult	REF:	2.5	TOP:	4
MSC:	Understanding		

	38.	The Moho ________.
a.	lies at uniform depth everywhere it is found in Earth	
b.	is found deeper underneath continents than under oceans	
c.	is found deeper underneath oceans than under continents	
d.	is found well below the crust/mantle boundary	

ANS:	B	DIF:	Easy	REF:	2.5	TOP:	4
MSC:	Applying

	39.	When you are warmed by the Sun, you are experiencing ________; when you burn yourself touching a metal object whose other end is being heated you are experiencing ________.
a.	advection; conduction	c.	radiation; convection	
b.	radiation; conduction	d.	advection; convection	

ANS:	B	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Applying

	40.	The image below shows ________, where a hot liquid rises into a cooler material, and heat then conducts from the hot liquid into the cooler material.

a.	advection	c.	convection	
b.	conduction	d.	radiation	

ANS:	A	DIF:	Difficult	REF:	2.5	TOP:	4
MSC:	Understanding		

	41.	From left to right, correctly label each section of this slice of the Earth. Note that 1 starts at the surface of the Earth and 6 ends at the center of the Earth.

a.	crust, liquid outer core, transition zone, solid inner core, upper mantle, lower mantle	
b.	crust, upper mantle, transition zone, lower mantle, liquid outer core, solid inner core	
c.	crust, transition zone, upper mantle, lower mantle, liquid outer core, solid inner core	
d.	transition zone, crust, liquid outer core, solid inner core, upper mantle, lower mantle	

ANS:	B	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Analyzing

	42.	As compared to the rocks that make up the crust, Earth as a whole is ________.
a.	considerably more dense	c.	slightly less dense	
b.	considerably less dense	d.	about the same density	

ANS:	A	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Applying

	43.	The velocities of seismic waves traveling from earthquake foci ________.
a.	are uniform throughout all layers of Earth	
b.	decrease at a constant rate with depth	
c.	increase at a constant rate with depth	
d.	generally increase with depth, but occasionally make abrupt jumps	

ANS:	D	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Understanding		

	44.	The boundary between the crust and the mantle is marked by an abrupt change in seismic velocity called the ________.
a.	transition zone	c.	low-velocity zone	
b.	Moho	d.	crantle	

ANS:	B	DIF:	Easy	REF:	2.5	TOP:	4
MSC:	Understanding		

	45.	Earth’s magnetic field is generated by the ________.
a.	flow of the liquid inner core	c.	convective flow of the mantle	
b.	flow of the liquid outer core	d.	magnetic minerals within the crust	

ANS:	B	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Applying

	46.	Which of the following statements about Earth’s core is NOT true?
a.	Its metallic content is likely similar to what has been found in metallic meteorites.	
b.	It is partly liquid and partly solid.	
c.	It is composed of an iron alloy (mostly iron with a few other metallic elements mixed in).	
d.	By volume, it is the largest compositional layer of the Earth.	

ANS:	D	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Analyzing

	47.	As compared to ultramafic rocks, mafic rocks have a ________.
a.	greater proportion of silica	
b.	lesser proportion of silica	
c.	greater proportion of iron and magnesium atoms	
d.	greater density	

ANS:	A	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Applying

	48.	In general, the mantle is made of the rock ________ and has a(n) ________ composition.
a.	granite; intermediate	c.	gabbro; mafic	
b.	basalt; mafic	d.	peridotite; ultramafic	

ANS:	D	DIF:	Medium	REF:	2.5	TOP:	4
MSC:	Understanding		

	49.	The lithosphere is composed of the ________.
a.	crust only	
b.	crust, mantle, and outer core	
c.	top 100 m of sediments and sedimentary rocks	
d.	crust and the uppermost part of the mantle	

ANS:	D	DIF:	Easy	REF:	2.6	TOP:	5
MSC:	Remembering		

	50.	The lithosphere lies directly above the ________.
a.	transition zone	c.	asthenosphere	
b.	crust	d.	lower mantle	

ANS:	C	DIF:	Easy	REF:	2.6	TOP:	5
MSC:	Understanding		

	51.	The distinction between the crust and the mantle is primarily on the basis of a difference in ________; the distinction between the lithosphere and the asthenosphere is primarily on the basis of a difference in ________.
a.	composition; the ability to flow without breaking	
b.	color; composition	
c.	the ability to flow without breaking; composition	
d.	composition; composition as well	

ANS:	A	DIF:	Medium	REF:	2.6	TOP:	5
MSC:	Understanding		

	52.	As compared to the asthenosphere, the lithosphere is ________.
a.	cooler and more able to flow	c.	cooler and less able to flow	
b.	hotter and more able to flow	d.	hotter and less able to flow	

ANS:	C	DIF:	Medium	REF:	2.6	TOP:	5
MSC:	Applying