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The Earth´s spheres

 

There are four layers or "spheres" in the earth. These "spheres" are interrelated. They are:

 

  • The geosphere: it is the solid part of the Earth.

  • The atmosphere: it is the gaseous part of the Earth.

  • The hydrosphere: it is the liquid part of the Earth.

  • The biosphere: it is the living part of the Earth.

The crust and the upper part of the upper mantle form the lithosphere, which is a layer divided into pieces called tectonic plates.

2. The atmosphere.

 

This is the layer of gases that surrounds the Earth. The mixture of gases that forms the atmosphere is called air.

 

 

3. The hydrosphere.

 

This is the discontinuous layer of water that covers the Earth. This water can be liquid, ice or vapour.

 

 

4. The biosphere.

 

This is the layer formed by all living beings in the earth. It constantly interacts with the lithosphere, the atmosphere and the hydrosphere.

ACTIVITIES

 

Search for new vocabulary and build up a particular section of related vocabulary.

 

1. Relate the following characteristics with the corresponding layer of the Earth.

 

a. It is just below the crust and made up of peridotite.

b. It contains all the water of the Earth.

c. It is the thinnest Earth´s layer.

d. It is composed of a mixture of gases called air.

e. It is divided into layers, the outer one is liquid.

 

 

2. Explain which are the main differences between:

 

a. the inner core and the outer core.

b. the upper mantle and the lower.

c. the continental crust and the ocenic crust.

 

 

3. Correct the following sentences:

 

​a. The lithosphere is the flexible outermost part of the Earth.

b. The crust and some of the core make up the lithosphere.

c. The lithosphere is a layer of semifluid rocks.

d. The atmosphere and the hydrosphere are solid layers.

e. The biosphere is composed of all living beings in the Universe.

1. The Geosphere.

 

The Earth´s inside is divided into three concentric layers:

 

a) The crust: it is the outermost layer of the Earth. It is ver thin, just only a few kilometers. It is solid and composed by silicates. There are two types of crust:

 

- Continental crust.

It makes up the continents and it is thicker than the oceanic crust. The most common rock on it is granite.

 

- Oceanic crust.

It makes up the ocean floor and it is thinner than the continental crust. The most common rock on it is basalt.

 

b) The mantle: it is the middle layer and it is situated just below the crust. It is a ver thick layer, about 2.900 km. It is a semi-solid layer and it is composed by a rock called peridotite. It is divided into two partes:

 

- The upper mantle.

- The lower mantle.

 

c) The core: it is the innermost layer and it is situated just below the mantle. It is the thickest layer, about 3.500 km, and its composition is manly iron. It is divided into two differente lyers:

 

- The outer core. It is liquid.

- The inner core. It is solid.

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