Science U4L2

Question 1

Convergent boundaries

Answer 1

the boundary between tectonic plates that are colliding

Question 2

Continental Drift

Answer 2

Theory that continents once formed a single landmass, broke up, and drifted.

Question 3

Sea-floor spreading

Answer 3

Process in which molten rock from inside Earth rises through the cracks in the ridges, cools, and forms new oceanic crust.

Question 4

Explain why cool rocks sink.

Answer 4

Cool rocks are denser so they sink

Question 5

Pangaea

Answer 5

Super-continent that formed 300 million years ago and that began to break up 200 million years ago

Question 6

What are the theories for the cause of movement of tectonic plates?

Answer 6

1. Mantle convection
2. Ridge push
3. Slab pull

Question 7

If the sea floor has been spreading for millions of years, why is Earth not getting larger?

Answer 7

Dense oceanic crust sinks into the trenches. As new crust is made, older crust is destroyed.

Question 8

What are the discoveries that support the idea of continental drift?

Answer 8

1. Age and Magnetic Properties of the sea floor
2. Sea-Floor Spreading
3. Ocean Trenches

Question 9

Tectonic plates

Answer 9

plates that move around on top of the asthenosphere.

the continents are on top of the tectonic plates and move with them

Question 10

Theory of Plate tectonics

Answer 10

Describes how large scale movements of Earth’s lithosphere

Question 11

Name three tectonic plates.

Answer 11

Pacific
North American
Nazca
South American
African
Australian
Eurasian
Indian
Antarctic

Question 12

What is the evidence that supports the theory of continental drift?

Answer 12

• In North America the Mountains are similar to those in Europe
• In South America you can find the same species of fossil on Africa

Question 13

ridge push

Answer 13

newly formed rock at a mid-ocean ridge is warm and less dense than older, adjacent rock and pushes up, while older rock pushes down

Question 14

Where does sea-floor spreading take place?

Answer 14

mid-ocean ridge

Question 15

Transformation boundary

Answer 15

boundary at which two plates move past each other horizontally

Question 16

Explain how the divergent boundaries relate to formation of new lithosphere.

Answer 16

Teh separation of the plates allow the asthenosphere to rise toward the surface and partially melt. The melting creates magma which erupts as larva creating new rock (mid-ocean ridge)

Question 17

What was the name of the ocean that surrounded Pangaea?

Answer 17

Panthalassa

Question 18

What are the three types of convergent boundaries?

Answer 18

1. Continent-continent Collisions
2. Continent-Ocean Collisions
3. Ocean-Ocean Collisions

Question 19

convection

Answer 19

movement of matter due to differences in density

Question 20

Which mechanism do scientist think is most important for plate movement?

Answer 20

Slab pull

Question 21

what do you call boundaries where one plate sinks beneath another plate?

Answer 21

Subduction zone

Question 22

What landform is likely to form at the convergent boundary?

Answer 22

Mountains

Question 23

How are transformation boundaries different from divergent or convergent?

Answer 23

Divergent and convergent boundaries create new rock formations.

Question 24

Are all of the plates the same size?

Answer 24

no

Question 25

Divergent boundary

Answer 25

area between two plates that move away from each other.