2+layers+of+the+Earth

Ryan Uy H1B Nathaniel Lim H1B Alfonso Panis H1C

The Earth's Interior

I. Crust
A. Outer most and thinnest layer of the earth B. Light and brittle C. Where earthquakes usually happen D. Broken into many pieces called plates which drift slowly E. Composed of silicon, aluminum, calcium, sodium and potassium F. Has two kinds:

1. Continental Crust
a. 2nd Smallest Part of the earth b. 0.374% of earth's mass c. 0-31 miles in depth d. less dense e. made of granite f. On top of the oceanic crust

2. Oceanic Crust
a. Smallest part of the earth b. 0.099% of the Earth's mass c. 0-6 miles in depth d. made of basalt e. dark and dense f. Lies at the bottom of the ocean

II. Mohorovicic Discontinuity
A. Discovered in 1909 by Andrija Mohorovicic B. Separates the crust and the mantle. C. Discovered by the change in speed of seismic waves when passing through this D. Depth of about 8 kilometers beneath the ocean basins and 32 kilometers beneath continental surfaces. E. Mohorovicic used this discovery to study thickness variations of the crust.

III. Mantle
A. Largest and thickest layer of the earth B. Found below the crust and above the core C. Comprises more than 80% of the earth's volume. D. Relatively flexible so it flows instead of fracturing at a rate of a few centimeters a year. E. Where magma comes from F. Convection currents in the mantle caused by the great difference of temperatures between the lower and upper mantle cause the lithosheric plates above it to move. G. Composed of silicon, oxygen, magnesium, iron, aluminum, and calcium H. The part of the upper mantle that exhibits plastic properties is called the Asthenosphere I. 1,700 miles (2,750 km) thick J. Has two kinds:

1. Upper Mantle
a. Not completely solid, may be partly liquid (molten rocks/minerals) b. 10.3% of Earth's mass, 6-250 miles in depth c. Cooler than the lower mantle d. Separated from the crust because of the Mohorovicic discontinuity e. about 1,600° F (870° C)

2. Lower mantle
a. 49.2% of the Earth’s mass b. 650-2,890 kilometers deep c. Composed of silicon, magnesium, and oxygen. d. Contains some iron, calcium, and aluminium e. Comprises of 72.9% of the mantle-crust mass, which makes the earth abundant in silicon, magnesium, and oxygen. f. Around 4,000-6,700° F (2,200-3,700° C)

IV. Lithosphere
A. Made up of the crust and the upper mantle B. It is composed of rigid and brittle rock.

V. Gutenberg discontinuity
A. Discovered by Beno Gutenberg B. Separates the Mantle from the Core C. Seismic Velocity discontinuity or change in acceleration between the mantle and the core D. About 2,600km beneath the earth

VI. Core
A. Separated from the mantle by the Gutenberg discontinuity B. 1/3 of the Earth's total mass C. Made mostly of Iron D. Has two kinds:

1. Outer Core
a. Composed of Iron and Nickel in their liquid states b. Very dense c. When iron flows, it generates a magnetic field, which results in the Earth's magnetic field. d. Radius is about 7,000 km across (4,300 miles)

2. Inner Core
a. Components are solid b. Extremely hot and has extremely high pressure that the metals squeeze together and are not able to move. c. It is the innermost and densest layer of the Earth d. Has temperatures up to about 13,000°F (7,200°C = 7,500 K) e. Has a radius of about 2,400 km (1,500 miles) f. About 1,800 miles (2,900 km) below the earth’s surface

VII. Breakthrough
A. A new layer of the Earth may have been discovered. B. Evidences were found by Geologists at the University of Illinois 1. waves pass through the layers of the Earth after earthquakes. 2. waves bend and reflect when this happens. 3. waves weren't a uniform shape of iron so geologists were surprised 4. They believe that another layer, the inner, inner core, caused the waves to bend differently.




 A. **Which boundary seperates the lower mantle and the core?** B. **Why is the inner core solid?** C. What causes the earth's magnetic field? D. Which is the thinnest layer of the earth? E. **The Litosphere is composed of which two layers?** F. Which layer does magma come from? G. Which boundary separates the upper mantle and the crust? H. Which is the thickest layer of the earth? I. This happens in the mantle, which causes the lithospheric plates to move. J. This is the new layer believed to have been discovered by Geologists of the University of Illinois.

4 The inner core is made up of ___ and ______ 5 As you go down the pressure _______ 6. Give two difference of crust and mantle 8. Give two difference of mantle and core 10. Rate the reporters based on presentation(2), content (1) and clarity (2)

Sources: 1.http://news.illinois.edu/news/08/0310core.html (used for the breakthough) 2. http://wwwf.countryday.net/facstf/ms/schniebec/Layers%20of%20Earth/Layers%20INFO%20Page.htm 3. http://library.thinkquest.org/28327/html/universe/solar_system/planets/earth/interior/layers_of_earth.html 4. http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Inside.shtml 5. http://science.jrank.org/pages/3177/Gutenberg-Discontinuity.html 6. http://www.encyclopedia.com/doc/1O13-Gutenbergdiscontinuity.html 7. http://geology.com/articles/mohorovicic-discontinuity.shtml