Earth's Internal Heat

Question 1

layers of the earth

Answer 1

crust, mantle, outer core, inner core

Question 2

Solid, rigid, outermost layer; broken into many pieces called plates.
* Transformed by exogenic due to the interaction of subsystems and endogenic processes caused by the earth’s internal heat

Answer 2

crust

Question 3

what elements are abundant on the rocks of the crust

Answer 3

silicates and aluminum (SiAl layer)

Question 4

oceanic crust

Answer 4

6-12 km, denser, basaltic

Question 5

continental crust

Answer 5

25-70 km thick, less dense, granitic

Question 6

temperature of crust

Answer 6

200°-400° C near the Moho

Question 7

Rocks are semi-solid; partly molten, and can flow
processes: Convection current - the circular motion of semi-solid materials due to the heat from the core
- upper and lower
- thickest layer

Answer 7

mantle

Question 8

what elements are abundant on the rocks of the mantle

Answer 8

silicates and magnesium (SiMa)

Question 9

how hot is the mantle

Answer 9

1000-3000 C

Question 10

how thick is the mantle, and what percent of the earth’s volume is it

Answer 10

2900 km; 83%

Question 11

zone of Earth’s mantle lying beneath the lithosphere and is believed to be much hotter and more fluid than the lithosphere.

• where magma is found

Answer 11

asthenosphere

Question 12

Liquid layer; rich in iron and nickel
(NiFe layer)
* The convection flow of materials
generates the _____________________

Answer 12

outer core; earth’s magnetic field

Question 13

how thick is the outer core

Answer 13

2,200 km

Question 14

how hot is the outer core

Answer 14

4,500-5,500 C

Question 15

Extreme pressure from overlying
squeezed the metals together
making this layer solid (Pressure
freezing)
* This layer’s gravitational force pulls all other layers towards itself

Answer 15

inner core

Question 16

how thick is the inner core, and what elements are abundant in it

Answer 16

1250 km radius; NiFe

Question 17

how hot is the inner core

Answer 17

5430-6000 C (hotter than the surface of the sun, hottest layer)

Question 18

the solid, outer part of Earth. includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth’s structure. It is bounded by the atmosphere above and the asthenosphere (another part of the upper mantle) below

Answer 18

lithosphere

Question 19

beneath the asthenosphere. It encompasses the upper mantle and lower mantle (where material still flows but at a much slower rate than the asthenosphere.)

Answer 19

mesosphere

Question 20

Earth’s most internal layer beneath the lithosphere. It is the innermost layer of the Earth and includes both the inner core and outer core and is composed of nickel and iron.

Answer 20

barysphere

Question 21

The transition zone between upper and lower Crust.

Answer 21

Conrad Discontinuity

Question 22

The transition zone between the Crust and Mantle

Answer 22

Mohorovicic Discontinuity

Question 23

The transition zone between Outer mantle and Inner mantle.

Answer 23

Repetti Discontinuity:

Question 24

The transition zone between Mantle and Core.

Answer 24

Gutenberg Discontinuity

Question 25

The transition zone between Outer core and Inner core.

Answer 25

Lehmann/Bullen Discontinuity

Question 26

The faster of the two types of body waves; they travel through solids and liquids but travel more slowly through liquids than solids
-can pass through both mantle and core, but are slowed and refracted at the mantle / core boundary at a depth of 2900 kms
- evidence for the solid inner core

Answer 26

P-waves

Question 27

The slower of the two types of body wave; not transmitted by liquids (or other fluids)
- this passing from the mantle to the core is absorbed because it cannot be transmitted through liquids. This is evidence that the outer core does not behave like a solid substance
- This produces a ‘shadow zone’ on certain parts of the Earth’s surface where S-waves are not recorded, and this is used as the main piece of evidence to deduce the size of the core. The core has a radius of 3470 km.

Answer 27

s-waves

Question 28

how are the properties of the earth’s layers discovered

Answer 28

through seismic waves

Question 29

how is the temperature of the core assumed

Answer 29

since the core generates the earth’s magnetic field that is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in the Earth’s outer core, it was assumed that the core is made up of iron and nickel. these compositions’ melting point is the core’s assumed temperature

Question 30

the transfer of kinetic energy from one medium or object to another, or from an energy source to a medium or object.

Answer 30

heat

Question 31

why is the earth’s interior hot?

Answer 31

due to the primordial heat and radioactive heat

Question 32

the internal heat energy accumulated by dissipation in a planet during its first few million years of evolution. The main contributions to the primordial heat are accretional energy – the energy deposited by infalling planetesimals – and differentiation energy.

• ancient heatLeftover heat from Earth’s
  Formation (Planetary
  Accretion)
• Friction due to the movement of
  heavy metals

early - rocks - inelastic collision - kinetic energy - heat - giant ball of lava/magma - cool down - stabilize - forming layers (bc of density) - movement - friction of metals - heat

Answer 32

primordial heat

Question 33

Any of innumerable small bodies of accreted gas and dust thought to have orbited the Sun during the formation of the planets

Answer 33

planetesimals

Question 34

meteoroid vs. meteor vs. meteorite

Answer 34

When meteoroids enter Earth’s atmosphere (or that of another planet, like Mars) at high speed and burn up, the fireballs or “shooting stars” are called meteors. When a meteoroid survives a trip through the atmosphere and hits the ground, it’s called a meteorite.

Question 35

Radioactive isotopes such as U-238, Th-232, K-40 in the core of the earth undergo spontaneous fission to produce more stable isotopes/elements. (radiation but very short, probably in mantle or crust)

Answer 35

radiogenic heat

Question 36

How does Heat travel
in the layers?

Answer 36

through

• conduction (from the inner core to the outer core)
• convection (outer core and mantle)
• radiation (radioactive isotopes)

Question 37

Transfer of heat in solid through direct contact

Answer 37

conduction

Question 38

Transfer of heat in fluids
(liquid and gas) through the circulation of matter

Answer 38

convection

Question 39

Transfer of heat through space by
waves

Answer 39

radiation

Question 40

The extreme temperature of the inner core could have molten the iron and nickel but it is believed to have solidified as a result of

Answer 40

pressure freezing

The temperature of the inner core is far above the melting point of iron. However, the inner core’s intense pressure—the entire rest of the planet and its atmosphere—prevents the iron from melting.