8th grade science 2

Question 1

Continental drift

Answer 1

Wegener’s hypothesis that all continents were once connected in a single large landmass that broke apart and drifted slowly to the current positions

Question 2

Pangaea

Answer 2

A single landmass composed of all continents joined together

Question 3

Seafloor spreading

Answer 3

Hesse’s theory that magna under Earth’s crust is forced up towards the surface at the mid ocean ridges, forming new seafloor

Question 4

Asthenosphere

Answer 4

Plastic like layer of earth on which the lithosphere plates move

Question 5

Convection currents

Answer 5

Cycle of heating, rising, cooling, and sinking

Question 6

Lithosphere

Answer 6

Rigid layer of Earth made of the crust and upper mantle that move on the asthenosphere

Question 7

Plate

Answer 7

Large section of Earth’s crust layer and upper mantle layer that moves around on the asthenosphere

Question 8

Plate tectonics

Answer 8

Theory that Earth’s crust and upper mantle are broken into plates that move around on a plastic like layer of mantle

Question 9

Earthquake

Answer 9

Movement of the ground that occurs when rocks inside Earth pass their elastic limit, break suddenly, and experience rebound

Question 10

Fault

Answer 10

Fracture that occurs where rocks break which results in movement of opposing sides

Question 11

Focus

Answer 11

Point deep inside Earth where energy is released, causing an earthquake

Question 12

Magnitude

Answer 12

Measure of energy released by an earthquake

Question 13

Seismic safe

Answer 13

Describes the ability of structures to stand up against vibrations caused by an earthquake

Question 14

Seismic waves

Answer 14

Earthquake waves including primary waves, secondary waves, and surface waves

Question 15

Seismograph

Answer 15

Instrument used to record seismic waves

Question 16

Tsunami

Answer 16

Powerful seismic sea wave that begins over an ocean floor earthquake

Question 17

Cinder cone volcano

Answer 17

Relatively small volcano formed by moderate to explosive eruptions of tephra

Question 18

Composite volcano

Answer 18

Steep sided volcano forms with alternating layers of violent eruptions of tephra and quieter interruptions of lava

Question 19

Lava

Answer 19

Molten rock flowing onto earths surface

Question 20

Shield volcano

Answer 20

Large, broad volcano with gently sloping sides that is formed by the buildup of basaltic layers

Question 21

Volcano

Answer 21

Cone shaped hill or mountain formed when hot magma, solids, and gases erupt onto earths surface through a vent

Question 22

Hot spot

Answer 22

Large body of magma that has been forced upward from deep within earth, which may cause volcanoes to form in the middle of a plate

Question 23

Rift

Answer 23

Long crack, fissure,or trough that forms between tectonic plates moving apart at tectonic boundaries