Chapter 2

Question 1

What is the primary significance of the habitable zone around a star

Answer 1

It can only be called a natural disaster if the impact has caused human casualties, extensive destruction of property, and significant economic loss

Question 2

Age of the earth - reversals

Answer 2

Polarity of the earth changes during different ages of the Earth

Question 3

Mineral

Answer 3

a naturally occurring, inorganic, crystalline solid with a definite chemical composition

Question 4

Rocks

Answer 4

naturally occurring solid consisting of mineral grains

Question 5

Intrusive Igneous Rock

Answer 5

made out of solidified magma

Question 6

Extrusive Igneous Rock

Answer 6

made out of solidified lava

Question 7

Sedimentary Rocks

Answer 7

composed of clasts that are eroded from a source area, transported by water, wind, or ice, and are deposited at the Earth’s surface and subsequently lithified

Question 8

Metamorphic Rocks

Answer 8

transformed from an existing rock into a new type of rock due to high heat and pressure from within the Earth

Question 9

What is the primary difference between a rock and a mineral?

Answer 9

A mineral has a definite chemical composition, while a rock is a composite of different minerals

Question 10

Rock Cycle: Igneous

Answer 10

Igneous rocks form from cooled magma or lava

Question 11

Rock Cycle: Weathering + Erosion

Answer 11

Breakdown of rocks into smaller particles by natural forces

Question 12

Rock Cycle: Sedimentary Rocks

Answer 12

Formed from compacted and cemented sediments

Question 13

Rock Cycle: Metamorphic Rocks

Answer 13

Formed from existing rocks under increased pressure and temp

Question 14

Rock Cycle: Magma Formation

Answer 14

Rocks melt under high pressure to become magma again

Question 15

Lithosphere

Answer 15

The rigid uppermost layer (“Plate”) of the earth. Includes the crust and uppermost layer of the mantle

Question 16

Crust

Answer 16

• 15% less dense than the mantle
• oceanic crust: 7-10 km thick, silica poor
• continental crust: 25-70 km thick, silica rich

Question 17

Alfred Wegener

Answer 17

• Proposed all continents were once connected and then drifted apart (named it Pangaea)
• Theory was initially rejected as he had no concrete evidence

Question 18

Evidence for Plate Tectonics

Answer 18

Seafloor spreading explained the force behind moving plates and recycling of oceanic lithosphere and gave information unobtainable via studying continents

Question 19

What is the role of the seafloor spreading played in the theory of plate tectonic theory

Answer 19

All of the above

Question 20

How fast do tectonic plates move?

Answer 20

About the rate your fingernails grow, a few centimeters a year

Question 21

Plate Boundaries

Answer 21

Divergent: away
Convergent: toward
Transform: horizontally (like cars on a street)

Question 22

Age of the Earth

Answer 22

4.6 Ga or 4600 Ma
Ga: billions of years
Ma: millions of years