Earth's Structure Flashcards
True or false: the earth’s overall density is twice that if the rocks near the surface. Explain your answer.
True, because the earths interior is very dense.
Formula for density?
Density=mass/volume
Why do the layers of the Earth have different densities?
Because they are made from different materials.
Do less dense layers float on the more dense layers?
Yes.
Is the crust solid or liquid? What are its layers called?
Solid, continental and oceanic
Is the mantle more solid or liquid? What word is used to describe it.
More solid than liquid ➡️ plastic
Is the outer core solid or liquid? What is it made of?
Liquid, iron and nickel
Is the inner core solid or liquid? What is it made of?
Solid, iron
What layers make up plates?
The crust and some of the upper mantle.
What thicknesses can the plates range from?
15km to 200km
True or false: all continents take up only part of their tectonic plate
True.
True or false: plates move steadily in definite directions.
True
What is used to prove the location of plate boundaries?
Large amounts of seismic, volcanic and geothermal activity.
How far do the continents move per year?
5-10cm
True or false: Australia will eventually crash into Asia
True
What part of the mantle do the plates sit over?
The plastic part.
Describe how plates move underneath each other. (Key words: leading edge, plastic)
The leading edge of the plate sinks under gravity and drags the rest of it with it, and the flow of the plastic rock in the mantle drags the plate from below.
How is density measured?
Mass by weight, volume by formulas or displacement
State the thicknesses of the oceanic, continental, mantle, outer core and inner core.
Oceanic - 10km Continental - 30km Mantle - 3000km Outer - 2300km Inner - 1200km
Difference between oceanic and continental crust?
Continental is deeper but less dense.
Where is the ring of fire located and why does it exist?
Located on the Pacific Plate border and exists because volcanoes are created because it’s near a border.
How do tsunamis occur?
Waves caused by earthquakes build up in height as the land gets shallower and they slow down and cause mass destruction.
Describe the December 26 2004 tsunami.
Sumatra-Andaman Tsunami reached 5000km away from the radius, killing 300,000 people across Asia and Africa.
Why does Australia have little volcanic activity?
Because Australia is in the middle of the Indo-Australian plate and not near the border where the action is
