Unit 1: Structure of the EarthUnit 1: Structure of the Earth

Standard:

Compare and Contrast the layers of the earth including composition, relative temperature, and density.

What challenges stand in the way of scientists exploring the center of the

Earth?

What challenges stand in the way of scientists exploring the center of the

Earth?• Deepest Mine

– Carletonville, South Africa 2 1/3 mile (3.8km)

• Deepest Geological Dig– Zapolyarnyy, Russia 9 miles (15km)

• Deepest Ocean Dive– Bathscaphe in Marianas Trench 6 miles

(10km)

• Deepest Ocean Trench– Marianas Trench, Pacific Ocean 7 miles

(11km)

What challenges stand in the way of scientists exploring the center of the

Earth?

What challenges stand in the way of scientists exploring the center of the

Earth?

• No equipment equipped to withstand the heat, pressure, and depth of the interior of the Earth.

• No human can withstand the heat, pressure, or depth of the interior of the Earth.

The composition of the EarthThe composition of the Earth

• The Earth is divided into three main layers – the crust, the mantle, and the core- based on the compounds that make up each layer. A compound is a substance composed of two or more elements. The least dense compounds make up the crust and mantle, the densest compounds make up the core. The layers form because heavier elements are pulled toward the center of the Earth by gravity, and the elements of lesser mass are found farther from the center.

The CrustThe Crust

• SOLID layer of rock that forms Earth’s outer skin, including the solid earth and oceans.

The CrustThe Crust

• Composition:Composition: mostly oxygen, silicon, aluminum, (Granite and Basalt)

• Relative Temperature:Relative Temperature: Vary from air temperature to 870 Co

• Density:Density: 2.7 - 3.3g/cm3

• Thickness: (5-100 km) 100km

CrustCrust

•Less than ___1___% of the earth’s mass.

•5 to __100___ km thick

•Temperature range is 0°C to 1000°C

•Least dense layer

•Continental crust is thicker than oceanic crust

•Oceanic crust is denser than continental because it’s made of denser minerals

•Avg. thickness- 35 km

•2 kinds

1. Continental

20-90 km thick; contains older rock, primarily granite

2. Oceanic

5-10 km thick; younger rock, primarily basalt

Crust Cont.Crust Cont.•All life exists in the crust of the Earth.

•Approximately 90 different elements are found in the crust, but 5 make up 90% of the crust; oxygen, silicon, aluminum, iron, & calcium

•Sodium, potassium, & magnesium are the most common elements in the remaining 10%

The MantleThe Mantle

• SOLID layer of hot rock between the crust and core.

The MantleThe Mantle

• CompositionComposition: Mostly iron and magnesium

• Relative TemperatureRelative Temperature: 870oC – 3,700oC

• DensityDensity: 3.3 - 5.7 g/cm3

• Thickness: (100km – 3,000km) 2,900km

MantleMantle•67% of the earth’s mass

•Much thicker than the crust

•Denser than the crust because it’s made of denser compounds

•contains 80% of Earth’s volume

•Common elements found in the mantle are: silicon, oxygen, aluminum, iron, & magnesium.

•The mantle consists of solid rock, except for the asthenosphere.

•Density increases in the mantle as depth increases

CrustCrust

Mantle

Lithosphere

Asthenosphere

Layers of the MantleLayers of the Mantle

The mantle is divided into 3 sections.

1. Lithosphere- consists of the uppermost part of the mantle (rigid rock) & the crust. Average thickness is 100 km.

- Moho’s discontinuity- boundary separating crust from mantle; discovered in 1909 using seismic data; found approximately 30 km from Earth’s surface

Layers of the Mantle cont.Layers of the Mantle cont.

2. Asthenosphere- 100-250 km deep; more fluid layer, but not liquid

3. Mesosphere- lowest layer; rigid rock; 660-2900 km deep

-temperature increases with depth, as does density

LithosphereLithosphere

• The layer formed by the upper part of the mantle and ALL the crust.

• Averages 100 km thick

AsthenosphereAsthenosphere

• Upper part of the Mantle.

• Molten (melted) rock layer.

• About 175 km thick.

• Plates float on it

The CoreThe Core

• Center of the Earth; under extreme pressure

The Outer CoreThe Outer Core

• Composition:Composition: LIQUID iron and nickel

• Relative TemperatureRelative Temperature: 3,700oC – 4,300oC

• Density:Density: 9.9 – 12.2 g/cm3

• Thickness:(3,000km – 5,200km) 2,200km

Outer Core (liquid)Outer Core (liquid)

•Approximately 2200 km thick

•Liquid; very dense molten iron & nickel

•Believed to create Earth’s magnetic field; similar to the magnetic field around a magnet

The Inner CoreThe Inner Core

• Composition:Composition: SOLID iron and nickel

• Relative TemperatureRelative Temperature: 4,300oC – 7,200oC

• Density:Density: 12.6 – 13.0 g/cm3

• Thickness: (5,200km – 6,428km)1,228km

Inner Core (solid)Inner Core (solid)•Densest layer because it’s made of the densest “stuff"

•Temperature is about 5000º Celsius

•Believed to be solid; very dense iron & nickel

•Remains solid due to immense pressure (may be 2 million times stronger than normal pressure exerted on Earth’s surface); molecules cannot spread out & become liquid

How does a hard boiled egg represent the layers of the Earth?

How does a hard boiled egg represent the layers of the Earth?

Which parts can you name?Which parts can you name?

Which parts can you name?Which parts can you name?

• More challenging