chapter 21

Question 1

crust

Answer 1

the thin and solid outermost layer of Earth above the mantle

Question 2

mantle

Answer 2

the layer of rock between earth’s crust and core. because S-waves travel through mantle, it has to be a solid

Question 3

earth’s core

Answer 3

the center of earth below the mantle, believed to be made of mostly iron and nickel inner core solid metal & outer core liquid metal.

Question 4

inner core

Answer 4

the pressure is so great that the atoms are forced together as a solid despite the intense heat.

Question 5

outer core

Answer 5

the pressure is so great that the substances are prevented from changing into gaseous form, so they stay liquid.

Question 6

lithosphere

Answer 6

the solid, outer layer of earth that consists of the crust and the rigid upper mantle.

Question 7

divergent boundary

Answer 7

occurs where two plates move apart, creating a gap between them. magma rises between the plates to fill the gap, creating a rift valley.

Question 8

magma

Answer 8

liquid rock produced under earth’s surface

Question 9

subduction

Answer 9

the process by which one lithospheric plate moves beneath another, as a result of tectonic forces. Ocean trenches, mountains, and volcanos are formed at subduction zones.

Question 10

fault

Answer 10

a crack in the earth created when rocks on either side of a break move.

Question 11

focus

Answer 11

the area along a fact at which the rift motion of an earthquake occurs. i.e.. the exact source of the earthquake

Question 12

epicenter

Answer 12

the point on earth’s surface directly above an earthquake’s focus.

Question 13

earthquake waves

Answer 13

Prime wave (P-wave): longitudinal wave. Secondary wave (s-wave) traverse wave. + surface waves.

Question 14

Surface waves

Answer 14

a seismic wave that only moves through solids. So the S wave do travel through the crust and the mantle, but not through the core, cuz the outer core is liquid.

Question 15

vent

Answer 15

an opening at the surface of earth through which volcanic material passes.

Question 16

a volcano

Answer 16

any opening in earth’s crust through which magma has reached earths surface.

Question 17

lava

Answer 17

when magma reaches the surface it’s physical behavior changes and it is called lava.

Question 18

3 types of volcanoes

Answer 18

(1) shield, (2) composite, (3) cinder.

Question 19

shield volcanoes:

Answer 19

have mild eruptions. Magma rich in iron and magnesium is very fluid and forms lava that tends to flow great distances.

Question 20

composite volcanoes

Answer 20

have trapped gas. Made up of alternating layers of ash, cinders, and lava. Their magma is rich in silica and therefore is much more viscous than the magma of a shield volcano.

Question 21

cinder cones

Answer 21

are the smallest and the most abundant volcanoes. When large amounts of gas are trapped in magma, violent eruptions occur — vast quantities of ash and lava are thrown from the vent.

Question 22

seamount

Answer 22

underwater volcano. occur at divergent plate boundaries.

Question 23

most volcanoes occur at

Answer 23

convergent plate boundaries.

Question 24

earthquakes occur as a result of sudden movement within earth’s …

Answer 24

lithosphere.

Question 25

most volcanoes occur at …

Answer 25

convergent plate boundaries.

Question 26

P-waves

Answer 26

are the longitudinal waves and they travel the fastest.

Question 27

S-waves

Answer 27

are transverse waves and they move more slowly. They travel only through solids – they can’t travel through the core cuz the outer core is liquid

Question 28

surface waves

Answer 28

travel the slowest, they result from the earth vibrating like a bell.

Question 29

mineral

Answer 29

a natural, usually inorganic ,solid that has a characteristic chemical composition, an orderly internal structure, and a characteristic set of physical quantities.

Question 30

igneous rock

Answer 30

rock that cools and solidifies when magma cools.

Question 31

obsidian

Answer 31

a smooth stone extrusive ingenious rock that cools much more quickly than granite. Obsidian has either very smalls crystals or no crystals at all and is mostly glass. Extrusive rock because it cools on the earth’s surface.

Question 32

Extrusive rock

Answer 32

it cools on the earth’s surface.

Question 33

Granite

Answer 33

intrusive igneous rock. coarse grained because it cools very slowly while trapped beneath the earth’s surface. Hence large crystals, because of long cooling time.

Question 34

sedimentary rock

Answer 34

a rock formed from compressed or cemented layers of sediment. Ex. limestone, a sedimentary rock, will turn into marble, sedimentary rock, under the effects of heat and pressure.

Question 35

metamorphic rock

Answer 35

a rock that forms from the other rocks as a result of intense heat, pressure, or chemical process.

Question 36

old rocks in the rock cycle create new rocks.

Answer 36

rocks can change type as described by the rock cycle.

Question 37

water expands ?% when it freezes.

Answer 37

~10% –> it can act as a wedge in weathering rocks.