Question

inside earth
the mantle
solid or liquid?
which types of waves move through the mantle?
why does this show if it is solid or liquid?
the outer core
solid or liquid?
which types of waves move through the outer core?
why does this show if it is solid or liquid?
the inner core
solid or liquid?
which types of waves move through the inner core?
why does this show if it is solid or liquid?

1. the crust

oceanic plates
what types of rock are they made of?
are they thin or thick?
are they light or dense?
are they old or young? why?
continental plates
what types of rock are they made of?
are they thin or thick?
are they light or dense?
are they old or young? why?

Explanation:

Part 1: Inside Earth (Mantle, Outer Core, Inner Core)

The Mantle

• Solid or Liquid?: Solid (it is a solid layer, though it can flow slowly over long periods, but in terms of primary state for seismic wave analysis, it's solid - like).
• Which types of Waves move through the Mantle?: Both P - waves (Primary waves, longitudinal) and S - waves (Secondary waves, transverse) move through the mantle.
• Why does this show if it is solid or liquid?: S - waves can only travel through solids. Since S - waves move through the mantle, this indicates that the mantle is solid (or has solid - like properties that allow S - wave propagation).

The Outer Core

• Solid or Liquid?: Liquid.
• Which types of Waves move through the Outer Core?: Only P - waves move through the outer core.
• Why does this show if it is solid or liquid?: S - waves cannot travel through liquids. Since S - waves do not pass through the outer core and only P - waves (which can travel through liquids and solids) do, this shows the outer core is liquid.

The Inner Core

• Solid or Liquid?: Solid.
• Which types of Waves move through the Inner Core?: Both P - waves and S - waves move through the inner core.
• Why does this show if it is solid or liquid?: S - waves can travel through solids. Since S - waves are able to move through the inner core, this indicates that the inner core is solid.

Part 2: The Crust (Oceanic Plates vs Continental Plates)

OCEANIC PLATES

• What types of rock are they made of?: Oceanic plates are mainly made of basalt (a type of igneous rock).
• Are they thin or thick?: Thin (typically around 5 - 10 kilometers thick).
• Are they light or dense?: Dense (basalt is denser than the rocks that make up continental plates).
• Are they old or young? Why?: Young. Because new oceanic crust is constantly being formed at mid - ocean ridges, and old oceanic crust is subducted (pushed down into the mantle) at trenches, so the oceanic crust has a relatively short lifespan (up to around 200 million years).

CONTINENTAL PLATES

• What types of rock are they made of?: Continental plates are mainly made of granite (a type of igneous rock) and also contain sedimentary and metamorphic rocks.
• Are they thin or thick?: Thick (typically around 30 - 70 kilometers thick, and can be even thicker in some mountainous regions).
• Are they light or dense?: Light (granite is less dense than basalt).
• Are they old or young? Why?: Old. Continental crust is not subducted (or subducted very rarely), so it can accumulate over time. Some parts of the continental crust are billions of years old.

Answer:

Part 1: Inside Earth (Mantle, Outer Core, Inner Core)

The Mantle

• Solid or Liquid?: Solid (it is a solid layer, though it can flow slowly over long periods, but in terms of primary state for seismic wave analysis, it's solid - like).
• Which types of Waves move through the Mantle?: Both P - waves (Primary waves, longitudinal) and S - waves (Secondary waves, transverse) move through the mantle.
• Why does this show if it is solid or liquid?: S - waves can only travel through solids. Since S - waves move through the mantle, this indicates that the mantle is solid (or has solid - like properties that allow S - wave propagation).

The Outer Core

• Solid or Liquid?: Liquid.
• Which types of Waves move through the Outer Core?: Only P - waves move through the outer core.
• Why does this show if it is solid or liquid?: S - waves cannot travel through liquids. Since S - waves do not pass through the outer core and only P - waves (which can travel through liquids and solids) do, this shows the outer core is liquid.

The Inner Core

• Solid or Liquid?: Solid.
• Which types of Waves move through the Inner Core?: Both P - waves and S - waves move through the inner core.
• Why does this show if it is solid or liquid?: S - waves can travel through solids. Since S - waves are able to move through the inner core, this indicates that the inner core is solid.

Part 2: The Crust (Oceanic Plates vs Continental Plates)

OCEANIC PLATES

• What types of rock are they made of?: Oceanic plates are mainly made of basalt (a type of igneous rock).
• Are they thin or thick?: Thin (typically around 5 - 10 kilometers thick).
• Are they light or dense?: Dense (basalt is denser than the rocks that make up continental plates).
• Are they old or young? Why?: Young. Because new oceanic crust is constantly being formed at mid - ocean ridges, and old oceanic crust is subducted (pushed down into the mantle) at trenches, so the oceanic crust has a relatively short lifespan (up to around 200 million years).

CONTINENTAL PLATES

• What types of rock are they made of?: Continental plates are mainly made of granite (a type of igneous rock) and also contain sedimentary and metamorphic rocks.
• Are they thin or thick?: Thick (typically around 30 - 70 kilometers thick, and can be even thicker in some mountainous regions).
• Are they light or dense?: Light (granite is less dense than basalt).
• Are they old or young? Why?: Old. Continental crust is not subducted (or subducted very rarely), so it can accumulate over time. Some parts of the continental crust are billions of years old.