Earth Science

Question 1

epicentre

Answer 1

the point on Earth’s surface directly above the focus of an earthquake

Question 2

erosion

Answer 2

the gradual wearing away and removal of rock at the surface of Earth

Question 3

igneous rock

Answer 3

a type of rock formed by the cooling and solidification of magma or lava

Question 4

lava

Answer 4

molten rock above Earth’s surface

Question 5

lithification

Answer 5

the process in which sediments come together to form sedimentary rock

Question 6

lithosphere

Answer 6

a layer of earth consisting of the crust and the lithospheric mantle

Question 7

magma

Answer 7

molten rock located below Earth’s surface

Question 8

metamorphic rock

Answer 8

a type of rock formed by heat and pressure

Question 9

mineral

Answer 9

a naturally-occurring, inorganic solid substance

Question 10

protolith

Answer 10

The original rock that has undergone metamorphism.

Question 11

rock cycle

Answer 11

an idealised series of processes undergone by rocks in Earth’s crust that change rocks from one type to another

Question 12

sedimentary rock

Answer 12

a type of rock formed by the accumulation and lithification of sediment

Question 13

subduction

Answer 13

a geological process at convergent boundaries where one tectonic plate sinks beneath another plate

Question 14

tsunami

Answer 14

a large ocean wave (or series of waves) caused by the displacement of large amounts of water, typically due to an earthquake or large landslide

Question 15

weathering

Answer 15

the gradual breakdown of rock while it remains in the same place; weathering can be caused by many things, including heating, cooling, wind, rain, chemical reactions, plant roots and human activity

Question 16

What is continental drift?

Answer 16

The theory that the continents were once joined to form the supercontinent ‘Pangea’, then broke apart into several continents over millions of years and drifted to their current positions.

Question 16

What are 3 pieces of evidence to support continental drift?

Answer 16

• Shapes of continents matching up at coastlines
• Similar plants and animal fossils of the same age across continents
• Mountain chains and rock types matching up

Question 16

What is the relative plate movement at convergent boundaries?

Answer 16

Growing closer

Question 17

What is the relative plate movement at divergent boundaries?

Answer 17

Growing apart

Question 18

What is the relative plate movement at transform boundaries?

Answer 18

Sliding along each other

Question 19

What boundary type is crust formed? What are the geographic features of this?

Answer 19

Divergent boundaries:
Oceanic oceanic - mid-ocean ridge, undersea volcanoes
Continental continental - rift valley, volcanoes

Question 20

What boundary type is crust destroyed? What are the geographic features of this?

Answer 20

Convergent boundaries:
Oceanic continental - oceanic trench (where crust sinks), volcanic arc (inland, wherre melted rock rises), oceanic crust sinks
Oceanic oceanic - oceanic trench (where crust sinks), volcanic island arc (islands formed by underwater volcanoes), denser crust sinks
Continental continental - mountain ranges, both crusts don’t sink and form high mountains

Question 21

What are the three types of rocks?

Answer 21

Igneous, sedimentary and metamorphic

Question 22

How are the three types of sedimentary rocks formed?

Clastic, chemical, biological

Answer 22

Clastic: formed from sediments of pre-existing rock, clasified by the size of sedimental grains (or clasts)
Biological: formed from remains of dead organisms (plant or animal)
Chemical: formed from dissolved minerals when water evaporates

Question 23

What are the three methods to form sedimentary rocks and how do they occur?

Compaction, cementation, recrystallisation

Answer 23

Compaction: Sediments are pressed together by pressure from overlying sediment
Cementation: Dissolved minerals in the water between sediment particles crystallise and cement the sediment particles together
Recrystallisation: minerals in the sediment exposed to water change their structure and recrystallise

Question 24

What are the two types of weathering and what causes them?

Mechanical, chemical

Answer 24

Mechanical weathering: no change in chemical composition, caused by temperature change, freezing/thawing of water, root action
Chemical weathering: change in chemical composition, caused by oxygen, rainwater, carbon dioxide

Question 25

What are the 5 major issues related to volcanic eruptions?

Answer 25

Toxic gases: harmful if inhaled, form acids when dissolved in water + cause acid rain/lake acidification
Lava flow: 700-1200 degrees celsius, usually slow so people can run away but fixed objects/plants cannot
Pyroclastic flow: mixture of solids, liquids and gases at over 1000 degrees, run down volcano like avalanch (>100km/h), deadliest aspect of volcano
Lahar: mudflow full of debris that can run down a volcano, acts like flash flood
Volcanic ash release: tiny fragments of minerals + rocks suspended in air like dust, fill alveoli in lungs and make it difficult to breathe, over plant leaves and prevent photosynthesis, darken sky and prevent sunlight from reaching ground, disrupt weather patterns

Question 26

What characteristics of P and S waves have provided information about the interior of Earth?

Answer 26

S-waves cannot travel through a liquid, but P-waves can. P-waves were detected travelling all the way to the other side of the earth but S-waves were not, so we can determine that the outer core is liquid.