Earth's Layers/Plate Tectonics Review

As you travel from the inner core to the crust, how would temperature, pressure and density of the material change?

• The would all increase
• The would all decrease.
• Nothing, the layers are made of the same material throughout
• Temperature would decrease, but pressure and density would increase

Scientists think that convection currents that move the plates flow in Earth's

• Continental crust
• oceanic crust
• Asthenosphere
• Lithosphere

Where does molten material from the mantle rise up during the process of sea-floor spreading?

• Along the mid-ocean ridge
• At the north and south poles 
• Along the edges of all the continents near the shoreline and beaches
• at the equator

Geologist believe the inner core is solid but hotter than the outer core which is liquid.  What is their reasoning for this?

• This is not what they believe.  Instead they think the inner core is liquid because with depth temperature increases causing the iron to melt.
• Because Earth is a sphere the interior takes on the same shape.
• Because all of the pressure from the overlying layers force the material to be a solid despite the hot temperatures.
• They have no evidence to support this claim, its just a guess.

The mantle of Earth is made of a plastic like material that when its heated, the material rises, cools, sinks and is then re-heated.  This constant flow of a fluid is called

• a conduction current
• a hot spot
• a volcanic eruption
• a convection current

How does sea floor spreading occur? 

• It is a myth and does not occur.
• At mid-ocean ridges, magma is forced upward and slowly spreads the plates 
• Organic material forms limestone on the ocean 
• The pressure from the ocean water forces down on the sea floor and moves it 

According to Wegener's hypothesis of continental drift,

• Earth is shrinking
• The continents do not move, they only appear to drift.
• The Earth once had great land bridges that connected the continents.
• The continents were once joined and have since drifted apart.

How would you describe the outer-core?

• liquid nitrogen
• liquid iron-rich
• solid iron-rich
• neither liquid nor solid, but plastic like layer

Where can the youngest rocks on Earth be found?

• along the coastlines of continents
• in the tallest mountain ranges on Earth
• at deep-ocean trenches where subduction occurs
• along the center of the mid-ocean ridges where sea-floor spreading occurs.

Which layer of Earth makes up the crust and the upper most part of the mantle.  This is the rigid layer that is broken into sections called plates.

• Crust
• Lithosphere
• Asthenosphere
• Mantle