The Earth

Question 1

The crust?

Answer 1

Outter layer, made of solid rock.

Question 2

The mantle?

Answer 2

Layer of hot soft rock that crust floats on, temp = 4,000 ℃ therefore rock is in molten state called magma.

Question 3

The core?

Answer 3

Center of the earth, made of nickel and iron, temp = 5,000℃+, outer core is molten, inner core is solid because of the pressure.

Question 4

Tectonic plates?

Answer 4

What the earth’s crust is divided into.

Question 5

Plate boundaries?

Answer 5

Where the plates meet.

Question 6

Plate tectonics?

Answer 6

Theory explaining the movements of the plates.

Question 7

3 types of plate boundaries?

Answer 7

Transform, destructive and constructive.

Question 8

Transform plate boundary?

Answer 8

Plates slide past each other, crust is neither created or destroyed.
Effects- fault lines and earthquakes.
Example- San Andreas Fault

Question 9

Destructive plate boundary?

Answer 9

Plates colliding, crust is destroyed, huge pressure build up causes heavier plate to be pushed downwards into mantle and get melted.
Effects- fold mountains, volcanic mountains, earthquakes.
Example- Nazca Plate & South American Plate or Indian plate & Eurasian Plate.

Question 10

Constructive plate boundary?

Answer 10

Plates separate, as plates pull apart molten magma rises from mantle and cools creating new crust.
Effects- mid-ocean ridges, volcanic islands, volcanic mountains.
Example- North American Plate separating from Eurasian and African Plates.

Question 11

Why do plates move?

Answer 11

Convection currents.

Question 12

What are convection currents?

Answer 12

Cores heats magma in mantle, magma near the core heats up, expands and gets lighter so it rises towards top. When it gets there it cools down because its moving away from the core and gets heavier so it sinks back down to the core then it reheats and starts the cycle again. This happens in a circular motion whether its clockwise or anti-clockwise (which is what causes the plates to move in different directions).

Question 13

Continental drift & Pangea?

Answer 13

The continents are floating on the plates, therefore, they move when the plates move. They move slowly and take millions of years to do so. The continents began as one large land mass called pangea and after 200 million years the continents got to where they are today. It’s still happening today given Europe is slowly moving away from North America, while India pushes northwards into Asia.

Question 14

Fold mountains?

Answer 14

Result of collision when two plates buckle up and crumple upwards creating folds in the earth’s crust.

Question 15

What are the 2 types of fold mountains?

Answer 15

Anticlines, which are upfolds.

Synclines, which are downfolds.

Question 16

Armorican folding?

Answer 16

Took place 250 million years ago when the Eurasian and African Plates collided. These mountains were once as high as the Alps but have been worn down severely.

Question 17

Alpine Folding?

Answer 17

Happened 30-35 million years ago, still very high and steep mountains as they have not yet been worn down as much as the older ones.

Question 18

Mid-ocean ridge?

Answer 18

Underwater mountain range caused by separating of plates. Iceland is one that’s part of the mid-atlantic ridge.

Question 19

Geothermal energy?

Answer 19

Created by hot water or steam from deep beneath earth’s surface converted into electricity.

Question 20

Volcanic mountains (volcanoes)?

Answer 20

Formed when molten magma emerges or erupts through a hole in the crust called a vent (usually found where plates separate or collide). When the magma reaches the surface its called lava, layers of lava build up around the vent, where it cools and hardens. As the mountain grows, the magma continues to make its way up through the pipe. The ash also helps build the cone. Lava continues to spill out through the crater and other materials, like gas, steam, rocks and boiling mud can escape during an eruption.

Question 21

Life cycle of a volcano? (3 stages + explanation)

Answer 21

Active- Still erupting regularly.
Dormant- Quiet, no eruptions for hundreds of years but may erupt again.
Extinct- Has not erupted in recorded times, thousands of years.

Question 22

Impacts of volcanic eruptions?

Answer 22

Environmental- can reduce height, new crater, forests affected, can cause mudflows or wipe out anything within a distance depending on gravity, kill any organism.
Human- Can emit toxic gasses to humans, deaths, injuries, homelessness.
Economic- Farms, homes, roads, railways, factories, etc.

Question 23

Earthquakes?

Answer 23

Sudden movement or trembling of the crust. Takes form of series of shock waves or tremors. They can occur at a ny plate boundary. Pressure builds up until a plate slips, releases a huge amount of energy and causes the earthquake. The focus is where the earthquake occurs and all the tremors start from that point. Epicenter is right over the focus but on the surface. Earthquakes can also have aftershocks hours or days after the main earthquake. Can be measured with a richter scale.

Question 24

Impacts of earthquakes?

Answer 24

Environmental- Earth’s crust moving, landslides, avalanches, harvests affected.
Human- Deaths, injuries, homelessness.
Economic- cost of rebuilding everything affected, tourism, cultural sites.