Geography

Question 1

What are the Earth’s layers?

Answer 1

Crust, mantle, outer core, inner core

Question 2

What are the properties of the Earth’s crust?

Answer 2

• Thickness of 5-50 km
• Split into different plates

Question 3

What are the properties of the mantle?

Answer 3

• Extends from 35-2980 km below the Earth’s surface
• Temperature between 200 - 4000°C
• Convection currents move the tectonic plates

Question 4

What are the properties of the outer core?

Answer 4

• Liquid
• 2000 km thick
• 2700 - 4900°C in outer region, 3700 - 6700°C in inner regions

Question 5

What are the properties of the inner core?

Answer 5

• Solid ballconsisting of iron and nickel
• 2400 km in diameter
• Temperature between 5200 - 5400°C

Question 6

What were Wegner’s evidence for his plate tectonic theory?

Answer 6

• Jigsaw fit
• Convection currents
• Fossil theory
• Palaeomagnetism

Question 7

What is jigsaw fit and what does it suggest?

Answer 7

Jigsaw fit is coastlines on opposite sides of oceans looking similar or as though they could fit together as jigsaw pieces, suggesting that all continents were once a supercontinent before they were pulled apart.

Question 8

What are convection currents and what do they suggest (in relation to plate tectonics theory)?

Answer 8

Molten rock in the mantle moves in circular currents, with hot rock rising, before then being cooled by the cooler temperatures nearer the surface and sinking again. These convection currents pull the plates with them, suggesting that movement in the mantle continually pulls and pushes tectonic plates away from and towards each other

Question 9

What is fossil theory and what does it suggest about plate tectonic theory?

Answer 9

Fossils of the same species from millions of years ago have been found on coastlines on opposite sides of oceans, often those that were unable to swim or fly. This suggests that there was once no gap in between the continents and the prehistoric animals roamed freely before the plates were pulled apart.