Investigacion

September, 5
Science
Look for the following information on the internet:
1. What is the Earth?
Earth (or the Earth) is the third planet from the Sun, and the densest and fifth-largest of theeight planets in the Solar System. It is also the largest of the Solar System's four terrestrial. It is sometimes referred to as the World, the Blue Planet.

2. Define what is the Crust, theMantle, and The Core.

* The crust ranges from 5–70 km in depth and is the outermost layer. The thin parts are the oceanic crust, which underlie the ocean basins (5–10 km) and are composed of dense(mafic) iron magnesium silicate rocks, like basalt.The thicker crust iscontinental crust, which is less dense and composed of (felsic) sodium potassiumaluminium silicate rocks, like granite. The rocksof the crust fall into two major categories - sial and sima (Suess,1831–1914). As the main mineral constituents of the continental mass are silica and alumina, it is thus called sial (si-silica,65–75% and al-alumina). The oceanic crust mainly consists of silica and magnesium. it is therefore called sima (si-silica and ma-magnesium). It is estimated that sima starts about 11 km below theConraddiscontinuity (a second order discontinuity). The uppermost mantle together with the crust constitutes the lithosphere. The crust-mantle boundary occurs as two physically different events. First, there isa discontinuity in the seismic velocity, which is known as theMohorovičić discontinuity or Moho. The cause of the Moho is thought to be a change in rock composition from rocks containing plagioclasefeldspar (above) to rocks that contain no feldspars (below). Second, in oceanic crust, there is a chemical discontinuity between ultramaficcumulates and tectonized harzburgites, which has been observedfrom deep parts of the oceanic crust that have been obducted onto the continental crust and preserved as ophiolite sequences.

* Earth's mantle extends to a depth of 2,890 km, making it the...