1. Earth’s Layers

2. WARM-UP Exploring Earth’s Interior (Article) 1. How did the author use the following as analogies in the reading? Pick TWO and briefly explain (use the article for help if you do not remember) Ford cars & World Series Brick traveling 45 minutes An apple’s skin Sidewalk in New York city & strand of spaghetti 2. How do we know the different layers exist?

3. Earth’s Layers (Article) Provide at least TWO facts about each layer of the Earth. What is the lithosphere & asthenosphere? Exploring Earth’s Interior (Article) What were the THREE main points of this part of the reading.

4. WARM-UP 1. How do you think pressure and temperature change as you move closer to the center of the Earth? Why?

5. Earth’s layers  Divided 2 different ways: 1.Composition (What it’s made of) 2.Physical Structure (Ex: solid or liquid)

6. Note: Denser material collects in the core because denser objects always sink due to gravity. Three layers based on composition: 1)2)3) Crust Mantle Core

7. A.Makes up 33% of the Earth’s mass B.Mostly Fe with some Ni (the denser elements) C.Little to No: O, Si, Al & Mg

8. A.Between the core and crust B.Contains most of the Earth’s mass (67%) C.Mostly Mg & Fe with some Si, O, & Al (more Mg than Al, because Mg is more dense) D.Temperature = 870 o C – 2200 o C E.Composition studied from volcanic eruptions

9. Oceanic Crust Continental Crust Continental Crust  Oceanic crust  Often composed of granite; mostly Si, O, Al, Ca, Na, K; thick & less dense Usually composed of basalt; mostly Si, O, Fe, Mg; thin & more dense Why does oceanic crust sit lower than continental crust? - Basalt is more dense than rocks in continental crust. Thin & solid, outer most layer (5 – 100 km thick)Thin & solid, outer most layer (5 – 100 km thick) up to 870 o C (increasing with depth)up to 870 o C (increasing with depth)

10. Five layers based on physical properties: 1)2)3)4)5) Lithosphere Asthenosphere Mesosphere Outer core Inner core 5 4 3 2 1

11. LithosphereAsthenosphereMesosphere 2 parts: rocky crust and rigid, outermost mantle 2 parts: rocky crust and rigid, outermost mantle TECTONIC PLATES!!!! TECTONIC PLATES!!!! Plastic (flowing) upper mantle directly beneath the lithosphere – Due to heat and pressure Plastic (flowing) upper mantle directly beneath the lithosphere – Due to heat and pressure Strong, dense lower layer of the mantle Strong, dense lower layer of the mantle

12. Why do you think the outer core is liquid, when the inner core is solid? Outer Core molten Fe & Ni – produces Earth’s magnetic fieldmolten Fe & Ni – produces Earth’s magnetic field Surrounds Inner CoreSurrounds Inner Core Temperature = 2200-5000  C Less pressure than inner core Inner Core Solid Fe & NiSolid Fe & Ni Temperature = 5000 o CTemperature = 5000 o C Extreme pressureExtreme pressure The intense pressure at the center of the Earth squeezes it into a solid!

13. When earthquakes occur, seismic waves (vibrations) are sent out in all directions, through the earth. These vibrations reach different places at different times because of the ways the waves… BEND and CHANGE SPEED as they pass through Earth’s layers.

15. Journey to the Center of the Earth (Discover June 2007) The deepest exploration ever: The Kola bore hole (about twice the size of a softball) the Russians drilled in the 70s and 80s reached a depth of 7.6 miles into the continental crust of Russia. They hit temps of 356 degrees F. But only reached a mere 0.2% of the way to the core. Most scientists agree the Earth’s core is sold iron and nickel, but some disagree Some think it could be like a nuclear reactor or even a massive crystal at the center. The question is will we ever reach the center to find out? One problem is trying to recreate the conditions of the Earth’s interior (pressure & heat) to test ways to explore its depths One geophysicist has an interesting idea – Open a crack in Earth’s crust with a controlled blast Then pour in 100,000 tons of liquid iron along with several refrigerator size probes Gravity should pull the liquid iron and probes down to the core in about one weeks time The path behind the iron would naturally seal its self up. The probes would communicate with the surface by seismic waves, sending up info about the cores. Why not do it? $$$$$