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

The Crust Composition:Composition: mostly oxygen, silicon, aluminum, (Granite and Basalt) Relative Temperature:Relative Temperature: Vary from air temperature to 870 C o Density:Density: g/cm3 Thickness: (5-100 km) 100km

Crust 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 km thick; contains older rock, primarily granite 2. Oceanic 5-10 km thick; younger rock, primarily basalt

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

The Mantle CompositionComposition: Mostly iron and magnesium Relative TemperatureRelative Temperature: 870 oC – 3,700 o C DensityDensity: g/cm3 Thickness: (100km – 3,000km) 2,900km

Mantle 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

Crust Mantle Lithosphere Asthenosphere

Layers 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. 2. Asthenosphere km deep; more fluid layer, but not liquid 3. Mesosphere- lowest layer; rigid rock; km deep -temperature increases with depth, as does density

Lithosphere The layer formed by the upper part of the mantle and ALL the crust. Averages 100 km thick

Asthenosphere Upper part of the Mantle. Molten (melted) rock layer. About 175 km thick. Plates float on it

The Core Center of the Earth; under extreme pressure

The Outer Core Composition:Composition: LIQUID iron and nickel Relative TemperatureRelative Temperature: 3,700 o C – 4,300 o C Density:Density: 9.9 – 12.2 g/cm3 Thickness:(3,000km – 5,200km) 2,200km

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 Core Composition:Composition: SOLID iron and nickel Relative TemperatureRelative Temperature: 4,300 o C – 7,200 o C Density:Density: 12.6 – 13.0 g/cm3 Thickness: (5,200km – 6,428km)1,228km

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?

Which parts can you name?

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