EARTH-AS-A-PLANet planet -WPS-Office.pptx

science

1. EARTH AS A PLANET

2. The Internal Structure of the Earth

3. What Really is Inside the Earth? Through the study of seismic waves, scientist inferred that our planet is made up of different layers. As seismic waves travel through the Earth, they are refracted and their speed gave vital information on the composition of the different layers of the Earth.

4. The structure of the Earth can be defined mechanically or chemically. Rheology is the study of the flow of matter primarily in the liquid state under conditions at which they respond with plastic flow rather than deforming elastically in response to an applied force.

5. Mechanically, the Earth can be divided into Five Layers: lithosphere, asthenosphere, mesospheric mantle, outer core, and inner core. Chemically, the layers of the Earth are as follows: crust, upper mantle, lower mantle, outer core, and inner core.

6. Lithosphere is the outer solid part of the planet including the Earth's crust as well as the underlying cool, dense, and rigid upper part of the mantle. depth of about 70-100 km. it is underlain by the asthenosphere. a highly viscous, hotter, and ductile region of the upper mantle that is involved in the plate tectonic movement and isostatic adjustment.

7. Core The innermost layer which is separated into the liquid outer core and solid inner core. It is the Earth’s source of internal heat. It is composed of iron and nickel alloy.

8. Inner Core Can be found at the deepest region of the earth. It has a temperature of 5,000-6,000°C or even higher than the temperature of the sun’s surface. It is solid and has a thickness of about 1,250km.

9. Outer Core Represents about 4% of the mantle-crust mass. Made up of iron, some nickel, and about 10% sulfur and oxygen. It has a temperature of about 5,000°C

10. Mantle The largest layer of the Earth. Composed of Fe, Al, Ca, Mg, Si, and O. makes up the 80% of Earth’s volume and 68% of Earth’s mass. Average temperature inside the mantle is about 3,700°C

11. The mantle is divided into two different zones: upper and lower mantle. Upper Mantle is a highly viscous layer which lies between the crust and the lower mantle. It extends up to 660 km. Lower Mantle extends from just under the upper mantle to 2,200 km

12. Mohorovicic discontinuity (Moho) separates the crust from the mantle discovered by Andrija Mohorovicic in 1909 inferred that the velocity of a seismic wave is related to the density of the material that is moving through. Occurs at an average depth of 8km beneath the ocean basins and 32km beneath the continental crust.

13. Crust the outer most layer of the Earth. the thinnest layer as it makes up only about 1% of the Earth. the thickest of this layer is dependent on its age- the thicker the layer, the older the crust.

14. Crust under the ocean, crust is only about 5-10 km thick. under the continents, the crust thickens up to 35 km depths up to 60 km under some mountain ranges.

15. Crust Composition the composition of the crust has been identified from scientific analyses of rocks and minerals. the most common elements in the crust by weight are O (46.6%), Si (27.7%), Al (8.1%), Fe (5%), Ca (3.6%), Na (2.8%), K (2.6%), Mg (2.1%).

16. Crust Composition These elements account for about 98.5% of the total weight of the crust. average temperature 870°C most earthquake occurs in the crust