Science

Question 1

Geology

Answer 1

the science that deals with the earth’s physical structure and substance, its history, and the processes that act on it.

Question 2

Lithosphere

Answer 2

the rigid, rocky outer layer of Earth, made up of the crust and the solid outermost layer of the upper mantle that extends a depth of about 60 miles

Question 3

Convergent Boundary

Answer 3

A tectonic boundary where two plates are moving toward each other

Question 4

Seismic Waves

Answer 4

In geology , shock waves in solid rock generated by earthquakes or underground explosions

Question 5

Asthenosphere

Answer 5

the region below the lithosphere, variously estimated as being from fifty to several hundred milesthick, in which the rock is less rigid than that above and below but rigid enough to transmit transverse seismic waves

Question 6

Pangaea

Answer 6

the hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago

Question 7

Divergent Boundary

Answer 7

A tectonic boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth’s surface between the two plates. The middle of the Red Sea and the mid-ocean ridge are divergent plate boundaries

Question 8

Magnetic Field

Answer 8

a region of space near a magnet, electric current, or moving charged particle in which a magnetic force acts on any other magnet, electric current, or moving charged particle

Question 9

Convection Current

Answer 9

heat-driven cycles that occur in the air, ocean, and mantle

Question 10

Seafloor Spreading

Answer 10

a process in which new ocean floor is created as molten material from the earth’s mantle rises in margins between plates or ridges and spreads out

Question 11

Trench

Answer 11

a long, narrow excavation in the ground, the earth from which is thrown up in front to serve as a shelter from enemy fire or attack

Question 12

Oceanic Crust

Answer 12

the outermost layer of Earth’s lithosphere that is found under the oceans and formed at spreading centres on oceanic ridges, which occur at divergent plate boundaries

Question 13

Tectonic Plates

Answer 13

The dozen or so plates that make up the surface of the Earth. Their motion is studied in the field of plate tectonics

Question 14

Plate Tectonics

Answer 14

a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past adjacent plates

Question 15

Mid-Ocean Ridge

Answer 15

any of several seismically active submarine mountain ranges that extend through the Atlantic, Indian, and Pacific Oceans: each is hypothesized to be the locus of seafloor spreading

Question 16

Continental Crust

Answer 16

any of several seismically active submarine mountain ranges that extend through the Atlantic, Indian, and Pacific Oceans: each is hypothesized to be the locus of seafloor spreading.

Question 17

Continental Drift

Answer 17

the lateral movement of continents resulting from the motion of crustal plates

Question 18

Transform Boundary

Answer 18

places where plates slide sideways past each other

Question 19

Subduction

Answer 19

the process by which collision of the earth’s crustal plates results in one plate’s being drawn down or overridden by another, localized along the juncture subduction zone of two plates

Question 20

Mantle

Answer 20

the portion of the earth, about 1,800 miles (2,900 km) thick, between the crust and the core

Question 21

Rift Valley

Answer 21

a subsea chasm extending along the crest of a mid-ocean ridge, locus of the magma upwellings that accompany seafloor spreading

Question 22

Volcano

Answer 22

a mountain or hill, usually having a cuplike crater at the summit, formed around such a vent from the ash and lava expelled through it

Question 23

Lava

Answer 23

molten rock ejected by volcanoes in the form of a liquid

Question 24

Magma

Answer 24

hot fluid or semifluid material below or within the earth’s crust from which lava and other igneous rock is formed on cooling

Question 25

Mesosphere

Answer 25

the region of the earth’s atmosphere above the stratosphere and below the thermosphere, between about 30 and 50 miles in altitude